Src kinase-associated phosphoprotein 1 Pleckstrin homology (PH) domain; Adaptor protein Skap1 (also called Skap55/Src kinase-associated phosphoprotein of 55 kDa) and its partner, ADAP (adhesion and degranulation promoting adapter protein) help reorganize the cytoskeleton and/or promote integrin-mediated adhesion upon immunoreceptor activation. Skap1 is also involved in T Cell Receptor (TCR)-induced RapL-Rap1 complex formation and LFA-1 activation. Skap1 has an N-terminal coiled-coil conformation which is proposed to be involved in homodimer formation, a central PH domain and a C-terminal SH3 domain that associates with ADAP. The Skap1 PH domain plays a role in controlling integrin function via recruitment of ADAP-SKAP complexes to integrins as well as in controlling the ability of ADAP to interact with the CBM signalosome and regulate NF-kappaB. SKAP1 is necessary for RapL binding to membranes in a PH domain-dependent manner and the PI3K pathway. Skap adaptor proteins couple receptors to cytoskeletal rearrangements. Skap55/Skap1, Skap2, and Skap-homology (Skap-hom) have an N-terminal coiled-coil conformation, a central PH domain and a C-terminal SH3 domain. Their PH domains bind 3'-phosphoinositides as well as directly affecting targets such as in Skap55 where it directly affecting integrin regulation by ADAP and NF-kappaB activation or in Skap-hom where the dimerization and PH domains comprise a 3'-phosphoinositide-gated molecular switch that controls ruffle formation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHSFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPHLRRDSKKESCFELTSQDRRS 163
Cdd:cd13380     1 ILKQGYLEKRSKDHSFFGSEWQKRWCVLTNRAFYYYASEKSKQPKGGFLIKGYSAQMAPHLRKDSRRDSCFELTTPGRRT 80

                          90       100
                  ....*....|....*....|....*.
gi 2462558451 164 YEFTATSPAEARDWVDQISFLLKDLS 189
Cdd:cd13380    81 YQFTAASPSEARDWVDQIQFLLKDTQ 106

Src kinase-associated phosphoprotein 1 Pleckstrin homology (PH) domain; Adaptor protein Skap1 (also called Skap55/Src kinase-associated phosphoprotein of 55 kDa) and its partner, ADAP (adhesion and degranulation promoting adapter protein) help reorganize the cytoskeleton and/or promote integrin-mediated adhesion upon immunoreceptor activation. Skap1 is also involved in T Cell Receptor (TCR)-induced RapL-Rap1 complex formation and LFA-1 activation. Skap1 has an N-terminal coiled-coil conformation which is proposed to be involved in homodimer formation, a central PH domain and a C-terminal SH3 domain that associates with ADAP. The Skap1 PH domain plays a role in controlling integrin function via recruitment of ADAP-SKAP complexes to integrins as well as in controlling the ability of ADAP to interact with the CBM signalosome and regulate NF-kappaB. SKAP1 is necessary for RapL binding to membranes in a PH domain-dependent manner and the PI3K pathway. Skap adaptor proteins couple receptors to cytoskeletal rearrangements. Skap55/Skap1, Skap2, and Skap-homology (Skap-hom) have an N-terminal coiled-coil conformation, a central PH domain and a C-terminal SH3 domain. Their PH domains bind 3'-phosphoinositides as well as directly affecting targets such as in Skap55 where it directly affecting integrin regulation by ADAP and NF-kappaB activation or in Skap-hom where the dimerization and PH domains comprise a 3'-phosphoinositide-gated molecular switch that controls ruffle formation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHSFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPHLRRDSKKESCFELTSQDRRS 163
Cdd:cd13380     1 ILKQGYLEKRSKDHSFFGSEWQKRWCVLTNRAFYYYASEKSKQPKGGFLIKGYSAQMAPHLRKDSRRDSCFELTTPGRRT 80

                          90       100
                  ....*....|....*....|....*.
gi 2462558451 164 YEFTATSPAEARDWVDQISFLLKDLS 189
Cdd:cd13380    81 YQFTAASPSEARDWVDQIQFLLKDTQ 106

PH domain; PH stands for pleckstrin homology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDhsfFGSEWQKRWCVVSRGLFYYYANE---KSKQPKGTFLIKGYSVRMAPHLrRDSKKESCFELTSQD 160
Cdd:pfam00169   1 VVKEGWLLKKGGG---KKKSWKKRYFVLFDGSLLYYKDDksgKSKEPKGSISLSGCEVVEVVAS-DSPKRKFCFELRTGE 76

                          90       100
                  ....*....|....*....|....*....
gi 2462558451 161 R---RSYEFTATSPAEARDWVDQISFLLK 186
Cdd:pfam00169  77 RtgkRTYLLQAESEEERKDWIKAIQSAIR 105

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*.
gi 2462558451  274 YYQGLWDCHGDQPDELSFQRGDLIRILSKMKVSkktlWQEASPDGKVCGFFFNNFL 329
Cdd:smart00326   4 QVRALYDYTAQDPDELSFKKGDIITVLEKSDDG----WWKGRLGRGKEGLFPSNYV 55

Src kinase-associated phosphoprotein 1 Pleckstrin homology (PH) domain; Adaptor protein Skap1 (also called Skap55/Src kinase-associated phosphoprotein of 55 kDa) and its partner, ADAP (adhesion and degranulation promoting adapter protein) help reorganize the cytoskeleton and/or promote integrin-mediated adhesion upon immunoreceptor activation. Skap1 is also involved in T Cell Receptor (TCR)-induced RapL-Rap1 complex formation and LFA-1 activation. Skap1 has an N-terminal coiled-coil conformation which is proposed to be involved in homodimer formation, a central PH domain and a C-terminal SH3 domain that associates with ADAP. The Skap1 PH domain plays a role in controlling integrin function via recruitment of ADAP-SKAP complexes to integrins as well as in controlling the ability of ADAP to interact with the CBM signalosome and regulate NF-kappaB. SKAP1 is necessary for RapL binding to membranes in a PH domain-dependent manner and the PI3K pathway. Skap adaptor proteins couple receptors to cytoskeletal rearrangements. Skap55/Skap1, Skap2, and Skap-homology (Skap-hom) have an N-terminal coiled-coil conformation, a central PH domain and a C-terminal SH3 domain. Their PH domains bind 3'-phosphoinositides as well as directly affecting targets such as in Skap55 where it directly affecting integrin regulation by ADAP and NF-kappaB activation or in Skap-hom where the dimerization and PH domains comprise a 3'-phosphoinositide-gated molecular switch that controls ruffle formation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHSFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPHLRRDSKKESCFELTSQDRRS 163
Cdd:cd13380     1 ILKQGYLEKRSKDHSFFGSEWQKRWCVLTNRAFYYYASEKSKQPKGGFLIKGYSAQMAPHLRKDSRRDSCFELTTPGRRT 80

                          90       100
                  ....*....|....*....|....*.
gi 2462558451 164 YEFTATSPAEARDWVDQISFLLKDLS 189
Cdd:cd13380    81 YQFTAASPSEARDWVDQIQFLLKDTQ 106

Src kinase-associated phosphoprotein homolog and Skap 2 Pleckstrin homology (PH) domain; Adaptor protein Skap-hom, a homolog of Skap55, which interacts with actin and with ADAP (adhesion and degranulation promoting adapter protein) undergoes tyrosine phosphorylation in response to plating of bone marrow-derived macrophages on fibronectin. Skap-hom has an N-terminal coiled-coil conformation that is involved in homodimer formation, a central PH domain and a C-terminal SH3 domain that associates with ADAP. The Skap-hom PH domain regulates intracellular targeting; its interaction with the DM domain inhibits Skap-hom actin-based ruffles in macrophages and its binding to 3'-phosphoinositides reverses this autoinhibition. The Skap-hom PH domain binds PI[3,4]P2 and PI[3,4,5]P3, but not to PI[3]P, PI[5]P, or PI[4,5]P2. Skap2 is a downstream target of Heat shock transcription factor 4 (HSF4) and functions in the regulation of actin reorganization during lens differentiation. It is thought that SKAP2 anchors the complex of tyrosine kinase adaptor protein 2 (NCK20/focal adhesion to fibroblast growth factor receptors at the lamellipodium in lens epithelial cells. Skap2 has an N-terminal coiled-coil conformation which interacts with the SH2 domain of NCK2, a central PH domain and a C-terminal SH3 domain that associates with ADAP (adhesion and degranulation promoting adapter protein)/FYB (the Fyn binding protein). Skap2 PH domain binds to membrane lipids. Skap adaptor proteins couple receptors to cytoskeletal rearrangements. Src kinase-associated phosphoprotein of 55 kDa (Skap55)/Src kinase-associated phosphoprotein 1 (Skap1), Skap2, and Skap-hom have an N-terminal coiled-coil conformation, a central PH domain and a C-terminal SH3 domain. Their PH domains bind 3'-phosphoinositides as well as directly affecting targets such as in Skap55 where it directly affecting integrin regulation by ADAP and NF-kappaB activation or in Skap-hom where the dimerization and PH domains comprise a 3'-phosphoinositide-gated molecular switch that controls ruffle formation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHSFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPHLRRDSKKESCFELTSQDRRS 163
Cdd:cd13381     1 VLKAGYLEKRRKDHSFFGFEWQKRWCALSNSVFYYYGSDKDKQQKGEFAIDGYDVKMNNTLRKDAKKDCCFEICAPDKRV 80

                          90       100
                  ....*....|....*....|....*
gi 2462558451 164 YEFTATSPAEARDWVDQISFLLKDL 188
Cdd:cd13381    81 YQFTAASPKEAEEWVQQIKFILQDL 105

SH3 domain-binding protein 2 Pleckstrin homology (PH) domain; SH3BP2 (the gene that encodes the adaptor protein 3BP2), HD, ITU, IT10C3, and ADD1 are located near the Huntington's Disease Gene on Human Chromosome 4pl6.3. SH3BP2 lies in a region that is often missing in individuals with Wolf-Hirschhorn syndrome (WHS). Gain of function mutations in SH3BP2 causes enhanced B-cell antigen receptor (BCR)-mediated activation of nuclear factor of activated T cells (NFAT), resulting in a rare, genetic disorder called cherubism. This results in an increase in the signaling complex formation with Syk, phospholipase C-gamma2 (PLC-gamma2), and Vav1. It was recently discovered that Tankyrase regulates 3BP2 stability through ADP-ribosylation and ubiquitylation by the E3-ubiquitin ligase. Cherubism mutations uncouple 3BP2 from Tankyrase-mediated protein destruction, which results in its stabilization and subsequent hyperactivation of the Src, Syk, and Vav signaling pathways. SH3BP2 is also a potential negative regulator of the abl oncogene. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHsFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPHLRrdSKKESCFEL--TSQDR 161
Cdd:cd13308     9 VIHSGTLTKKGGSQ-KTLQNWQLRYVIIHQGCVYYYKNDQSAKPKGVFSLNGYNRRAAEERT--SKLKFVFKIihLSPDH 85

                          90       100
                  ....*....|....*....|
gi 2462558451 162 RSYEFTATSPAEARDWVDQI 181
Cdd:cd13308    86 RTWYFAAKSEDEMSEWMEYI 105

Pleckstrin homology (PH) domain; PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEKKSKDHSFfgsEWQKRWCVVSRGLFYYYANEK--SKQPKGTF-LIKGYSVRMAPhlrrDSKKESCFELTSQDRR 162
Cdd:cd00821     1 KEGYLLKRGGGGLK---SWKKRWFVLFEGVLLYYKSKKdsSYKPKGSIpLSGILEVEEVS----PKERPHCFELVTPDGR 73

                          90
                  ....*....|....*....
gi 2462558451 163 SYEFTATSPAEARDWVDQI 181
Cdd:cd00821    74 TYYLQADSEEERQEWLKAL 92

Phosphoinositol 3-phosphate binding proteins 1, 2, and 3 pleckstrin homology (PH) domain; PEPP1 (also called PLEKHA4/PH domain-containing family A member 4 and RHOXF1/Rhox homeobox family member 1), and related homologs PEPP2 (also called PLEKHA5/PH domain-containing family A member 5) and PEPP3 (also called PLEKHA6/PH domain-containing family A member 6), have PH domains that interact specifically with PtdIns(3,4)P3. Other proteins that bind PtdIns(3,4)P3 specifically are: TAPP1 (tandem PH-domain-containing protein-1) and TAPP2], PtdIns3P AtPH1, and Ptd- Ins(3,5)P2 (centaurin-beta2). All of these proteins contain at least 5 of the 6 conserved amino acids that make up the putative phosphatidylinositol 3,4,5- trisphosphate-binding motif (PPBM) located at their N-terminus. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  81 LDNVIKQGYLEKKSkdhsffGS---EWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPHLRRDSKKEScFELT 157
Cdd:cd13248     4 NAPVVMSGWLHKQG------GSglkNWRKRWFVLKDNCLYYYKDPEEEKALGSILLPSYTISPAPPSDEISRKFA-FKAE 76

                          90       100
                  ....*....|....*....|....*
gi 2462558451 158 SQDRRSYEFTATSPAEARDWVDQIS 182
Cdd:cd13248    77 HANMRTYYFAADTAEEMEQWMNAMS 101

Src Homology 3 domain of Src Kinase-Associated Phosphoprotein 2; SKAP2, also called SKAP55-Related (SKAP55R) or SKAP55 homolog (SKAP-HOM or SKAP55-HOM), is an immune cell-specific adaptor protein that plays an important role in adhesion and migration of B-cells and macrophages. Binding partners include ADAP (adhesion and degranulation-promoting adaptor protein), YopH, SHPS1, and HPK1. SKAP2 has also been identified as a substrate for lymphoid-specific tyrosine phosphatase (Lyp), which has been implicated in a wide variety of autoimmune diseases. It contains a pleckstrin homology (PH) domain, a C-terminal SH3 domain, and several tyrosine phosphorylation sites. Like SKAP1, SKAP2 is expected to bind primarily to a proline-rich region of ADAP through its SH3 domain; its degradation may be regulated by ADAP. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20
                  ....*....|....*....|....*....
gi 2462558451 274 YYQGLWDCHGDQPDELSFQRGDLIRILSK 302
Cdd:cd12045     1 FYQGLWDCTGDQPDELSFKRGDTIYILSK 29

General Receptor for Phosphoinositides-1-like Pleckstrin homology (PH) domain; GRP1/cytohesin3 and the related proteins ARNO (ARF nucleotide-binding site opener)/cytohesin-2 and cytohesin-1 are ARF exchange factors that contain a pleckstrin homology (PH) domain thought to target these proteins to cell membranes through binding polyphosphoinositides. The PH domains of all three proteins exhibit relatively high affinity for PtdIns(3,4,5)P3. Within the Grp1 family, diglycine (2G) and triglycine (3G) splice variants, differing only in the number of glycine residues in the PH domain, strongly influence the affinity and specificity for phosphoinositides. The 2G variants selectively bind PtdIns(3,4,5)P3 with high affinity,the 3G variants bind PtdIns(3,4,5)P3 with about 30-fold lower affinity and require the polybasic region for plasma membrane targeting. These ARF-GEFs share a common, tripartite structure consisting of an N-terminal coiled-coil domain, a central domain with homology to the yeast protein Sec7, a PH domain, and a C-terminal polybasic region. The Sec7 domain is autoinhibited by conserved elements proximal to the PH domain. GRP1 binds to the DNA binding domain of certain nuclear receptors (TRalpha, TRbeta, AR, ER, but not RXR), and can repress thyroid hormone receptor (TR)-mediated transactivation by decreasing TR-complex formation on thyroid hormone response elements. ARNO promotes sequential activation of Arf6, Cdc42 and Rac1 and insulin secretion. Cytohesin acts as a PI 3-kinase effector mediating biological responses including cell spreading and adhesion, chemotaxis, protein trafficking, and cytoskeletal rearrangements, only some of which appear to depend on their ability to activate ARFs. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  83 NVIKQGYLEKKSKDHSffgsEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPhlrrDSKKESCFEL------ 156
Cdd:cd01252     2 NPDREGWLLKLGGRVK----SWKRRWFILTDNCLYYFEYTTDKEPRGIIPLENLSVREVE----DKKKPFCFELyspsng 73

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|
gi 2462558451 157 -------TSQDRR-------SYEFTATSPAEARDWVDQIS 182
Cdd:cd01252    74 qvikackTDSDGKvvegnhtVYRISAASEEERDEWIKSIK 113

Sesquipedalian family Pleckstrin homology (PH) domain; The sesquipedalian family has 2 mammalian members: Ses1 and Ses2, which are also callled 7 kDa inositol polyphosphate phosphatase-interacting protein 1 and 2. They play a role in endocytic trafficking and are required for receptor recycling from endosomes, both to the trans-Golgi network and the plasma membrane. Members of this family form homodimers and heterodimers. Sesquipedalian interacts with inositol polyphosphate 5-phosphatase OCRL-1 (INPP5F) also known as Lowe oculocerebrorenal syndrome protein, a phosphatase enzyme that is involved in actin polymerization and is found in the trans-Golgi network and INPP5B. Sesquipedalian contains a single PH domain. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEKKSKDHSFFgsewQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAphlrrDSKKESCFELT--SQDRRS 163
Cdd:cd13288    10 KEGYLWKKGERNTSY----QKRWFVLKGNLLFYFEKKGDREPLGVIVLEGCTVELA-----EDAEPYAFAIRfdGPGARS 80

                          90
                  ....*....|....*....
gi 2462558451 164 YEFTATSPAEARDWVDQIS 182
Cdd:cd13288    81 YVLAAENQEDMESWMKALS 99

Fungal proteins Pleckstrin homology (PH) domain, repeat 1; The functions of these fungal proteins are unknown, but they all contain 2 PH domains. This cd represents the first PH repeat. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  80 ELDNVIKQGYLEKKSKDHSFfgseWQKRWCVVSRGLFYYYANEKSKQPKGTF-LIKGYSVrmAPHlrRDSKKESCFELTS 158
Cdd:cd13298     2 EFDRVLKSGYLLKRSRKTKN----WKKRWVVLRPCQLSYYKDEKEYKLRRVInLSELLAV--APL--KDKKRKNVFGIYT 73

                          90       100
                  ....*....|....*....|...
gi 2462558451 159 QDrRSYEFTATSPAEARDWVDQI 181
Cdd:cd13298    74 PS-KNLHFRATSEKDANEWVEAL 95

Pleckstrin homology (PH) domain containing, family H (with MyTH4 domain) members 1 and 2 (PLEKHH1) PH domain, repeat 1; PLEKHH1 and PLEKHH2 (also called PLEKHH1L) are thought to function in phospholipid binding and signal transduction. There are 3 Human PLEKHH genes: PLEKHH1, PLEKHH2, and PLEKHH3. There are many isoforms, the longest of which contain a FERM domain, a MyTH4 domain, two PH domains, a peroximal domain, a vacuolar domain, and a coiled coil stretch. The FERM domain has a cloverleaf tripart structure (FERM_N, FERM_M, FERM_C/N, alpha-, and C-lobe/A-lobe, B-lobe, C-lobe/F1, F2, F3). The C-lobe/F3 within the FERM domain is part of the PH domain family. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEK---KSKDhsffgseWQKRWCVVSRGLFYYYA--NEKSKQPKGTFLIKGYSvRMAPhlrrdSKKESCFELTSqD 160
Cdd:cd13282     1 KAGYLTKlggKVKT-------WKRRWFVLKNGELFYYKspNDVIRKPQGQIALDGSC-EIAR-----AEGAQTFEIVT-E 66

                          90       100       110
                  ....*....|....*....|....*....|
gi 2462558451 161 RRSYEFTATSPAEARDWVDQISFLLKDLSS 190
Cdd:cd13282    67 KRTYYLTADSENDLDEWIRVIQNVLRRQAS 96

Myosin X Pleckstrin homology (PH) domain, repeat 2; MyoX, a MyTH-FERM myosin, is a molecular motor that has crucial functions in the transport and/or tethering of integrins in the actin-based extensions known as filopodia, microtubule binding, and in netrin-mediated axon guidance. It functions as a dimer. MyoX walks on bundles of actin, rather than single filaments, unlike the other unconventional myosins. MyoX is present in organisms ranging from humans to choanoflagellates, but not in Drosophila and Caenorhabditis elegans.MyoX consists of a N-terminal motor/head region, a neck made of 3 IQ motifs, and a tail consisting of a coiled-coil domain, a PEST region, 3 PH domains, a myosin tail homology 4 (MyTH4), and a FERM domain at its very C-terminus. The first PH domain in the MyoX tail is a split-PH domain, interupted by the second PH domain such that PH 1a and PH 1b flanks PH 2. The third PH domain (PH 3) follows the PH 1b domain. This cd contains the second PH repeat. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEKKSKDHSFFGSE-WQKRWCVVSRGLFYYYAN-EKSKQPKGTFlikgySVRMAPHLRRDSKKESCFELTSQDRrS 163
Cdd:cd13296     1 KSGWLTKKGGGSSTLSRRnWKSRWFVLRDTVLKYYENdQEGEKLLGTI-----DIRSAKEIVDNDPKENRLSITTEER-T 74

                          90
                  ....*....|....*....
gi 2462558451 164 YEFTATSPAEARDWVDQIS 182
Cdd:cd13296    75 YHLVAESPEDASQWVNVLT 93

SifA and kinesin-interacting protein Pleckstrin homology (PH) domain; SKIP (also called PLEKHM2/Pleckstrin homology domain-containing family M member 2) is a soluble cytosolic protein that contains a RUN domain and a PH domain separated by a unstructured linker region. SKIP is a target of the Salmonella effector protein SifA and the SifA-SKIP complex regulates kinesin-1 on the bacterial vacuole. The PH domain of SKIP binds to the N-terminal region of SifA while the N-terminus of SKIP is proposed to bind the TPR domain of the kinesin light chain. The opposite side of the SKIP PH domain is proposed to bind phosphoinositides. TSifA, SKIP, SseJ, and RhoA family GTPases are also thought to promote host membrane tubulation. Recently, it was shown that the lysosomal GTPase Arl8 binds to the kinesin-1 linker SKIP and that both are required for the normal intracellular distribution of lysosomes. Interestingly, two kinesin light chain binding motifs (WD) in SKIP have now been identified to match a consensus sequence for a kinesin light chain binding site found in several proteins including calsyntenin-1/alcadein, caytaxin, and vaccinia virus A36. SKIP has also been shown to interact with Rab1A. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEKKSKDHSFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAphlRR--DSKKESCFELTSQDRRS 163
Cdd:cd13309     2 KEGMLMYKTGTSYLGGETWKPGYFLLKNGVLYQYPDRSDRLPLLSISLGGEQCGGC---RRinNTERPHTFELILTDRSS 78

                          90
                  ....*....|....
gi 2462558451 164 YEFTATSPAEARDW 177
Cdd:cd13309    79 LELAAPDEYEASEW 92

ArfGAP with coiled-coil, ankyrin repeat and PH domains Pleckstrin homology (PH) domain; ACAP (also called centaurin beta) functions both as a Rab35 effector and as an Arf6-GTPase-activating protein (GAP) by which it controls actin remodeling and membrane trafficking. ACAP contain an NH2-terminal bin/amphiphysin/Rvs (BAR) domain, a phospholipid-binding domain, a PH domain, a GAP domain, and four ankyrin repeats. The AZAPs constitute a family of Arf GAPs that are characterized by an NH2-terminal pleckstrin homology (PH) domain and a central Arf GAP domain followed by two or more ankyrin repeats. On the basis of sequence and domain organization, the AZAP family is further subdivided into four subfamilies: 1) the ACAPs contain an NH2-terminal bin/amphiphysin/Rvs (BAR) domain (a phospholipid-binding domain that is thought to sense membrane curvature), a single PH domain followed by the GAP domain, and four ankyrin repeats; 2) the ASAPs also contain an NH2-terminal BAR domain, the tandem PH domain/GAP domain, three ankyrin repeats, two proline-rich regions, and a COOH-terminal Src homology 3 domain; 3) the AGAPs contain an NH2-terminal GTPase-like domain (GLD), a split PH domain, and the GAP domain followed by four ankyrin repeats; and 4) the ARAPs contain both an Arf GAP domain and a Rho GAP domain, as well as an NH2-terminal sterile-a motif (SAM), a proline-rich region, a GTPase-binding domain, and five PH domains. PMID 18003747 and 19055940 Centaurin can bind to phosphatidlyinositol (3,4,5)P3. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEKKSkdHSFFGSeWQKRWCVVSRGLFYYYANEKSKQPKGTFL-IKGYSVRMA--PHLRrdskkeSCFELTSQDrR 162
Cdd:cd13250     1 KEGYLFKRS--SNAFKT-WKRRWFSLQNGQLYYQKRDKKDEPTVMVEdLRLCTVKPTedSDRR------FCFEVISPT-K 70

                          90
                  ....*....|....*....
gi 2462558451 163 SYEFTATSPAEARDWVDQI 181
Cdd:cd13250    71 SYMLQAESEEDRQAWIQAI 89

Arf-GAP with GTPase, ANK repeat and PH domain-containing protein Pleckstrin homology (PH) domain; AGAP (also called centaurin gamma; PIKE/Phosphatidylinositol-3-kinase enhancer) reside mainly in the nucleus and are known to activate phosphoinositide 3-kinase, a key regulator of cell proliferation, motility and vesicular trafficking. There are 3 isoforms of AGAP (PIKE-A, PIKE-L, and PIKE-S) the longest of which PIKE-L consists of N-terminal proline rich domains (PRDs), followed by a GTPase domain, a split PH domain (PHN and PHC), an ArfGAP domain and two ankyrin repeats. PIKE-S terminates after the PHN domain and PIKE-A is missing the PRD region. Centaurin binds phosphatidlyinositol (3,4,5)P3. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  85 IKQGYLEKKSKDHsfFGSEWQ-KRWCVVSRGLFYYYANEK----SKQPKGTFLIKgYSVRMA-PHLRRDSKKESC-FELT 157
Cdd:cd01250     5 IKQGYLYKRSSKS--LNKEWKkKYVTLCDDGRLTYHPSLHdymeNVHGKEIDLLR-TTVKVPgKRPPRASSKSAFeFIIV 81

                          90       100
                  ....*....|....*....|....*
gi 2462558451 158 SQDRRSYEFTATSpAEARD-WVDQI 181
Cdd:cd01250    82 SLDGKQWHFEAAS-SEERDeWVQAI 105

Dual Adaptor for Phosphotyrosine and 3-Phosphoinositides Pleckstrin homology (PH) domain; DAPP1 (also known as PHISH/3' phosphoinositide-interacting SH2 domain-containing protein or Bam32) plays a role in B-cell activation and has potential roles in T-cell and mast cell function. DAPP1 promotes B cell receptor (BCR) induced activation of Rho GTPases Rac1 and Cdc42, which feed into mitogen-activated protein kinases (MAPK) activation pathways and affect cytoskeletal rearrangement. DAPP1can also regulate BCR-induced activation of extracellular signal-regulated kinase (ERK), and c-jun NH2-terminal kinase (JNK). DAPP1 contains an N-terminal SH2 domain and a C-terminal pleckstrin homology (PH) domain with a single tyrosine phosphorylation site located centrally. DAPP1 binds strongly to both PtdIns(3,4,5)P3 and PtdIns(3,4)P2. The PH domain is essential for plasma membrane recruitment of PI3K upon cell activation. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEKKSKdhsfFGSEWQKRWCVVSRGLFYYYANEKSKQPkgtflIKGYSVRMAPHLRRD--SKKESCFELTSQDRRS 163
Cdd:cd10573     5 KEGYLTKLGG----IVKNWKTRWFVLRRNELKYFKTRGDTKP-----IRVLDLRECSSVQRDysQGKVNCFCLVFPERTF 75

                          90       100
                  ....*....|....*....|..
gi 2462558451 164 YEFtATSPAEARDWVDQISFLL 185
Cdd:cd10573    76 YMY-ANTEEEADEWVKLLKWKL 96

Pleckstrin homology (PH) domain; Budding yeast contain two main p21-activated kinases (PAKs), Cla4 and Ste20. The yeast Ste20 protein kinase is involved in pheromone response, though the function of Ste20 mammalian homologs is unknown. Cla4 is involved in budding and cytokinesis and interacts with Cdc42, a GTPase required for polarized cell growth as is Pak. Cla4 and Ste20 kinases share a function in localizing cell growth with respect to the septin ring. They both contain a PH domain, a Cdc42/Rac interactive binding (CRIB) domain, and a C-terminal Protein Kinase catalytic (PKc) domain. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLekKSKDHSFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSvrmapHLRRDSKKESCFEL-TSQDRR 162
Cdd:cd13279     1 VVKSGWV--SVKEDGLLSFRWSKRYLVLREQSLDFYKNESSSSASLSIPLKDIS-----NVSRTDLKPYCFEIvRKSSTK 73

                          90
                  ....*....|....*....
gi 2462558451 163 SYEFTATSPAEARDWVDQI 181
Cdd:cd13279    74 SIYISVKSDDELYDWMDDI 92

Connector enhancer of KSR (Kinase suppressor of ras) (CNK) pleckstrin homology (PH) domain; CNK family members function as protein scaffolds, regulating the activity and the subcellular localization of RAS activated RAF. There is a single CNK protein present in Drosophila and Caenorhabditis elegans in contrast to mammals which have 3 CNK proteins (CNK1, CNK2, and CNK3). All of the CNK members contain a sterile a motif (SAM), a conserved region in CNK (CRIC) domain, and a PSD-95/DLG-1/ZO-1 (PDZ) domain, and a PH domain. A CNK2 splice variant CNK2A also has a PDZ domain-binding motif at its C terminus and Drosophila CNK (D-CNK) also has a domain known as the Raf-interacting region (RIR) that mediates binding of the Drosophila Raf kinase. This cd contains CNKs from insects, spiders, mollusks, and nematodes. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  87 QGYLEKKSKDHsFFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPHLRrdSKKEScFEL--TSQdrrSY 164
Cdd:cd13326     2 QGWLYQRRRKG-KGGGKWAKRWFVLKGSNLYGFRSQESTKADCVIFLPGFTVSPAPEVK--SRKYA-FKVyhTGT---VF 74

                          90
                  ....*....|....*..
gi 2462558451 165 EFTATSPAEARDWVDQI 181
Cdd:cd13326    75 YFAAESQEDMKKWLDLL 91

Dedicator of cytokinesis-D subfamily Pleckstrin homology (PH) domain; DOCK-D subfamily (also called Zizimin subfamily) consists of Dock9/Zizimin1, Dock10/Zizimin3, and Dock11/Zizimin2. DOCK-D has a N-terminal DUF3398 domain, a PH-like domain, a Dock Homology Region 1, DHR1 (also called CZH1), a C2 domain, and a C-terminal DHR2 domain (also called CZH2). Zizimin1 is enriched in the brain, lung, and kidney; zizimin2 is found in B and T lymphocytes, and zizimin3 is enriched in brain, lung, spleen and thymus. Zizimin1 functions in autoinhibition and membrane targeting. Zizimin2 is an immune-related and age-regulated guanine nucleotide exchange factor, which facilitates filopodial formation through activation of Cdc42, which results in activation of cell migration. No function has been determined for Zizimin3 to date. The N-terminal half of zizimin1 binds to the GEF domain through three distinct areas, including CZH1, to inhibit the interaction with Cdc42. In addition its PH domain binds phosphoinositides and mediates zizimin1 membrane targeting. DOCK is a family of proteins involved in intracellular signalling networks. They act as guanine nucleotide exchange factors for small G proteins of the Rho family, such as Rac and Cdc42. There are 4 subfamilies of DOCK family proteins based on their sequence homology: A-D. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHSFFGS-----EWQKRWCVVSR---GLFY--YYANEKSKQPKGT-FLIKGYSVRMAPHLRRdskkeS 152
Cdd:cd13267     6 ITKEGYLYKGPENSSDSFIslamkSFKRRFFHLKQlvdGSYIleFYKDEKKKEAKGTiFLDSCTGVVQNSKRRK-----F 80

                          90       100
                  ....*....|....*....|....*.
gi 2462558451 153 CFELTSQDRRSYEFTATSPAEARDWV 178
Cdd:cd13267    81 CFELRMQDKKSYVLAAESEAEMDEWI 106

Rho GTPase activating protein 24 Pleckstrin homology (PH) domain; RhoGap24 (also called ARHGAP24, p73RhoGAp, and Filamin-A-associated RhoGAP) like other RhoGAPs are involved in cell polarity, cell morphology and cytoskeletal organization. They act as GTPase activators for the Rac-type GTPases by converting them to an inactive GDP-bound state and control actin remodeling by inactivating Rac downstream of Rho leading to suppress leading edge protrusion and promotes cell retraction to achieve cellular polarity and are able to suppress RAC1 and CDC42 activity in vitro. Overexpression of these proteins induces cell rounding with partial or complete disruption of actin stress fibers and formation of membrane ruffles, lamellipodia, and filopodia. Members here contain an N-terminal PH domain followed by a RhoGAP domain and either a BAR or TATA Binding Protein (TBP) Associated Factor 4 (TAF4) domain. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  83 NVIKQGYLEKKSKdhsfFGSEWQKRWCVVSRGLFYYYANEKSKQPKGTFLIKGYSVRMAPhLRRDSKKESCFELT----- 157
Cdd:cd13379     2 EVIKCGWLRKQGG----FVKTWHTRWFVLKGDQLYYFKDEDETKPLGTIFLPGNRVTEHP-CNEEEPGKFLFEVVpggdr 76

                          90       100
                  ....*....|....*....|....*..
gi 2462558451 158 ---SQDRRSYEFTATSPAEARDWVDQI 181
Cdd:cd13379    77 ermTANHETYLLMASTQNDMEDWVKSI 103

Pleckstrin 2 Pleckstrin homology (PH) domain, repeat 2; Pleckstrin is a protein found in platelets. This name is derived from platelet and leukocyte C kinase substrate and the KSTR string of amino acids. Pleckstrin 2 contains two PH domains and a DEP (dishvelled, egl-10, and pleckstrin) domain. Unlike pleckstrin 1, pleckstrin 2 does not contain obvious sites of PKC phosphorylation. Pleckstrin 2 plays a role in actin rearrangement, large lamellipodia and peripheral ruffle formation, and may help orchestrate cytoskeletal arrangement. The PH domains of pleckstrin 2 are thought to contribute to lamellipodia formation. This cd contains the second PH domain repeat. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  83 NVIKQGYLEKKSKDHsffgsEWQKRWCVVSR---GLFYYYANEKSKQPKGTFLIKG---YSVRMAPHLRRDSKKESCFEL 156
Cdd:cd13302     6 IIVKQGCLLKQGHRR-----KNWKVRKFVLRddpAYLHYYDPAKGEDPLGAIHLRGcvvTAVEDNSNPRKGSVEGNLFEI 80

                          90       100
                  ....*....|....*....|....*
gi 2462558451 157 TSQDRRSYEFTATSPAEARDWVDQI 181
Cdd:cd13302    81 ITADEVHYYLQAATPAERTEWIKAI 105

Src Homology 3 domain superfamily; Src Homology 3 (SH3) domains are protein interaction domains that bind proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. Thus, they are referred to as proline-recognition domains (PRDs). SH3 domains are less selective and show more diverse specificity compared to other PRDs. They have been shown to bind peptide sequences that lack the PxxP motif; examples include the PxxDY motif of Eps8 and the RKxxYxxY sequence in SKAP55. SH3 domain containing proteins play versatile and diverse roles in the cell, including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies, among others. Many members of this superfamily are adaptor proteins that associate with a number of protein partners, facilitating complex formation and signal transduction.

                          10        20
                  ....*....|....*....|....*....
gi 2462558451 274 YYQGLWDCHGDQPDELSFQRGDLIRILSK 302
Cdd:cd00174     1 YARALYDYEAQDDDELSFKKGDIITVLEK 29

Snf1p-interacting protein 3 Pleckstrin homology (PH) domain; SIP3 interacts with SNF1 protein kinase and activates transcription when anchored to DNA. It may function in the SNF1 pathway. SIP3 contain an N-terminal Bin/Amphiphysin/Rvs (BAR) domain followed by a PH domain. BAR domains form dimers that bind to membranes, induce membrane bending and curvature, and may also be involved in protein-protein interactions. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  86 KQGYLEKKSKDHSFFGSEWQKRWCVVSRGLFYYYANEKSKQ-----PK-GTFLIkgySVRMAPhlrrDSKKESCFELTSQ 159
Cdd:cd13280     2 KSGWLYMKTSVGKPNRTIWVRRWCFVKNGVFGMLSLSPSKTyveetDKfGVLLC---SVRYAP----EEDRRFCFEVKIF 74

                          90
                  ....*....|....*....
gi 2462558451 160 DRRSYEFTATSPAEARDWV 178
Cdd:cd13280    75 KDISIILQAETLKELKSWL 93

RAS p21 protein activator (GTPase activating protein) 1 Pleckstrin homology (PH) domain; RASA1 (also called RasGap1 or p120) is a member of the RasGAP family of GTPase-activating proteins. RASA1 contains N-terminal SH2-SH3-SH2 domains, followed by two C2 domains, a PH domain, a RasGAP domain, and a BTK domain. Splice variants lack the N-terminal domains. It is a cytosolic vertebrate protein that acts as a suppressor of RAS via its C-terminal GAP domain function, enhancing the weak intrinsic GTPase activity of RAS proteins resulting in the inactive GDP-bound form of RAS, allowing control of cellular proliferation and differentiation. Additionally, it is involved in mitogenic signal transmission towards downstream interacting partners through its N-terminal SH2-SH3-SH2 domains. RASA1 interacts with a number of proteins including: G3BP1, SOCS3, ANXA6, Huntingtin, KHDRBS1, Src, EPHB3, EPH receptor B2, Insulin-like growth factor 1 receptor, PTK2B, DOK1, PDGFRB, HCK, Caveolin 2, DNAJA3, HRAS, GNB2L1 and NCK1. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  83 NVIKQGYLEKKSKDHSffgsEWQKRWCVV--SRGLFYYYANEKSKQPKGTFLIKG---YSVRMAPHLRRDskkesCFELT 157
Cdd:cd13260     2 GIDKKGYLLKKGGKNK----KWKNLYFVLegKEQHLYFFDNEKRTKPKGLIDLSYcslYPVHDSLFGRPN-----CFQIV 72

                          90       100
                  ....*....|....*....|....*
gi 2462558451 158 SQ---DRRSYEFTATSPAEARDWVD 179
Cdd:cd13260    73 VRalnESTITYLCADTAELAQEWMR 97

TBC1 domain family member 2A pleckstrin homology (PH) domain; TBC1D2A (also called PARIS-1/Prostate antigen recognized and identified by SEREX 1 and ARMUS) contains a PH domain and a TBC-type GTPase catalytic domain. TBC1D2A integrates signaling between Arf6, Rac1, and Rab7 during junction disassembly. Activated Rac1 recruits TBC1D2A to locally inactivate Rab7 via its C-terminal TBC/RabGAP domain and facilitate E-cadherin degradation in lysosomes. The TBC1D2A PH domain mediates localization at cell-cell contacts and coprecipitates with cadherin complexes. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  88 GYLEKKSKdHSFFGSEWQKRWCVV--SRGLFYYYANEKSKQPKGTFLIKGYSVRMAPhlrrdSKKESCFELTSQDrRSYE 165
Cdd:cd01265     4 GYLNKLET-RGLGLKGWKRRWFVLdeSKCQLYYYRSPQDATPLGSIDLSGAAFSYDP-----EAEPGQFEIHTPG-RVHI 76

                          90
                  ....*....|....*
gi 2462558451 166 FTATSPAEARDWVDQ 180
Cdd:cd01265    77 LKASTRQAMLYWLQA 91

Third Src Homology 3 domain (SH3C) of CD2-associated protein and similar proteins; This subfamily is composed of the third SH3 domain (SH3C) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3C of both proteins have been shown to bind to ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 2462558451 274 YYQGLWDCHGDQPDELSFQRGDLIRILSKMKVSKKtlWQEASPDGKVcGFFFNNF 328
Cdd:cd11875     1 KARVLFDYEAENEDELTLREGDIVTILSKDCEDKG--WWKGELNGKR-GVFPDNF 52

Grb2-associated binding protein family Pleckstrin homology (PH) domain; Gab proteins are scaffolding adaptor proteins, which possess N-terminal PH domains and a C-terminus with proline-rich regions and multiple phosphorylation sites. Following activation of growth factor receptors, Gab proteins are tyrosine phosphorylated and activate PI3K, which generates 3-phosphoinositide lipids. By binding to these lipids via the PH domain, Gab proteins remain in proximity to the receptor, leading to further signaling. While not all Gab proteins depend on the PH domain for recruitment, it is required for Gab activity. There are 3 families: Gab1, Gab2, and Gab3. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHSFFGSEWQKRWCVVSRG-------LFYYYANEKSKQPKGTFLIKGYSVRMA--PHLRRDSKKESCF 154
Cdd:cd13324     1 VVYEGWLTKSPPEKKIWRAAWRRRWFVLRSGrlsggqdVLEYYTDDHCKKLKGIIDLDQCEQVDAglTFEKKKFKNQFIF 80

                          90       100
                  ....*....|....*....|....*...
gi 2462558451 155 ELTSQDrRSYEFTATSPAEARDWVDQIS 182
Cdd:cd13324    81 DIRTPK-RTYYLVAETEEEMNKWVRCIC 107

GAP1(IP4BP) pleckstrin homology (PH) domain; GAP1 (also called IP4BP, RASA3/Ras GTPase-activating protein 3, and RAS p21 protein activator (GTPase activating protein) 3/GAPIII/MGC46517/MGC47588)) is a member of the GAP1 family of GTPase-activating proteins, along with RASAL1, GAP1(m), and CAPRI. With the notable exception of GAP1(m), they all possess an arginine finger-dependent GAP activity on the Ras-related protein Rap1. GAP1(IP4BP) contains two C2 domains, a PH domain, a RasGAP domain, and a BTK domain. Its C2 domains, like those of GAP1M, do not contain the C2 motif that is known to be required for calcium-dependent phospholipid binding. GAP1(IP4BP) is regulated by the binding of its PH domains to phophoinositides, PIP3 (phosphatidylinositol 3,4,5-trisphosphate) and PIP2 (phosphatidylinositol 4,5-bisphosphate). It suppresses RAS, enhancing the weak intrinsic GTPase activity of RAS proteins resulting in the inactive GDP-bound form of RAS, allowing control of cellular proliferation and differentiation. GAP1(IP4BP) binds tyrosine-protein kinase, HCK. Members here include humans, chickens, frogs, and fish. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  84 VIKQGYLEKKSKDHSFFG-SEWQKRWCVVSRGLFYYYaneKSKQPKGTFLIKGYSVRMAPHLRRDS-KKESCFELTSQDR 161
Cdd:cd13371    16 LLKEGFMIKRAQGRKRFGmKNFKKRWFRLTNHEFTYH---KSKGDHPLCSIPIENILAVERLEEESfKMKNMFQVIQPER 92

                          90
                  ....*....|....*...
gi 2462558451 162 RSYeFTATSPAEARDWVD 179
Cdd:cd13371    93 ALY-IQANNCVEAKDWID 109

Beta-spectrin pleckstrin homology (PH) domain; ARHGAP family genes encode Rho/Rac/Cdc42-like GTPase activating proteins with RhoGAP domain. The ARHGAP members here all have a PH domain upstream of their C-terminal RhoGAP domain. Some have additional N-terminal SH3 and WW domains. The members here include: ARHGAP9, ARHGAP12, ARHGAP15, and ARHGAP27. ARHGAP27 and ARHGAP12 shared the common-domain structure, consisting of SH3, WW, PH, and RhoGAP domains. The PH domain of ArhGAP9 employs a non-canonical phosphoinositide binding mechanism, a variation of the spectrin- Ins(4,5)P2-binding mode, that gives rise to a unique PI binding profile, namely a preference for both PI(4,5)P2 and the PI 3-kinase products PI(3,4,5)P3 and PI(3,4)P2. This lipid binding mechanism is also employed by the PH domain of Tiam1 and Slm1. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2462558451  85 IKQGYLE--------KKSKDHsffgseWQKRWCVVSRGLFYYYANEKSKQ--------PKGTFLIKGYSVRMAPHLrrdS 148
Cdd:cd13233     1 EKQGLLNktkiaengKKLRKN------WSTSWVVLTSSHLLFYKDAKSAAksgnpyskPESSVDLRGASIEWAKEK---S 71

                          90       100       110
                  ....*....|....*....|....*....|....
gi 2462558451 149 KKESCFELTSQDRRSYEFTATSPAEARDWVDQIS 182
Cdd:cd13233    72 SRKNVFQISTVTGTEFLLQSDNDTEIREWFDAIK 105

C-terminal (or second) Src Homology 3 domain of the p67phox subunit of NADPH oxidase; p67phox, also called Neutrophil cytosol factor 2 (NCF-2), is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p67phox plays a regulatory role and contains N-terminal TPR, first SH3 (or N-terminal or central SH3), PB1, and C-terminal SH3 domains. It binds, via its C-terminal SH3 domain, to a proline-rich region of p47phox and upon activation, this complex assembles with flavocytochrome b558, the Nox2-p22phox heterodimer. Concurrently, RacGTP translocates to the membrane and interacts with the TPR domain of p67phox, which leads to the activation of NADPH oxidase. The PB1 domain of p67phox binds to its partner PB1 domain in p40phox, and this facilitates the assembly of p47phox-p67phox at the membrane. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2462558451 274 YYQGLWDCHGDQPDELSFQRGDLIRILSkmKVSKKtlWQEASPDGKVcGFFFNNFL 329
Cdd:cd12046     1 QVVALFSYEASQPEDLEFQKGDVILVLS--KVNED--WLEGQCKGKI-GIFPSAFV 51