Src homology 3 domain of JNK-interacting proteins 1 and 2, and similar domains; JNK-interacting proteins (JIPs) function as scaffolding proteins for c-Jun N-terminal kinase (JNK) signaling pathways. They bind to components of Mitogen-activated protein kinase (MAPK) pathways such as JNK, MKK, and several MAP3Ks such as MLK and DLK. There are four JIPs (JIP1-4); all contain a JNK binding domain. JIP1 and JIP2 also contain SH3 and Phosphotyrosine-binding (PTB) domains. Both are highly expressed in the brain and pancreatic beta-cells. JIP1 functions as an adaptor linking motor to cargo during axonal transport and also is involved in regulating insulin secretion. JIP2 form complexes with fibroblast growth factor homologous factors (FHFs), which facilitates activation of the p38delta MAPK. The SH3 domain of JIP1 homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAYAVD 329
Cdd:cd11801   1 THRALHKFIPRHEDEIELDIGDPVYVEQEADDLWCEGTNLRTGQRGIFPAAYVVE 55

Src homology 3 domain of JNK-interacting proteins 1 and 2, and similar domains; JNK-interacting proteins (JIPs) function as scaffolding proteins for c-Jun N-terminal kinase (JNK) signaling pathways. They bind to components of Mitogen-activated protein kinase (MAPK) pathways such as JNK, MKK, and several MAP3Ks such as MLK and DLK. There are four JIPs (JIP1-4); all contain a JNK binding domain. JIP1 and JIP2 also contain SH3 and Phosphotyrosine-binding (PTB) domains. Both are highly expressed in the brain and pancreatic beta-cells. JIP1 functions as an adaptor linking motor to cargo during axonal transport and also is involved in regulating insulin secretion. JIP2 form complexes with fibroblast growth factor homologous factors (FHFs), which facilitates activation of the p38delta MAPK. The SH3 domain of JIP1 homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAYAVD 329
Cdd:cd11801   1 THRALHKFIPRHEDEIELDIGDPVYVEQEADDLWCEGTNLRTGQRGIFPAAYVVE 55

Phosphotyrosine interaction domain (PTB/PID);

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632   351 YLGSVETLAHK------GTGVVCQAVR--------KIVGEYGNSPTGQTCILEVSDQGLRMVDrsgpnqnkKDKKPCIdY 416
Cdd:pfam00640   5 YLGSVEVPEERapdkntRMQQAREAIRrvkaakinKIRGLSGETGPGTKVDLFISTDGLKLLN--------PDTQELI-H 75

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 17979632   417 FYSLKNVSFCA-FHPRDHRFIGFITKHPTVQRFACHVFKGSESTRPVAEAVGRAFQ 471
Cdd:pfam00640  76 DHPLVSISFCAdGDPDLMRYFAYIARDKATNKFACHVFESEDGAQDIAQSIGQAFA 131

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 17979632    275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRtGRQGIFPSAY 326
Cdd:smart00326   4 QVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRLGR-GKEGLFPSNY 54

Src homology 3 domain of JNK-interacting proteins 1 and 2, and similar domains; JNK-interacting proteins (JIPs) function as scaffolding proteins for c-Jun N-terminal kinase (JNK) signaling pathways. They bind to components of Mitogen-activated protein kinase (MAPK) pathways such as JNK, MKK, and several MAP3Ks such as MLK and DLK. There are four JIPs (JIP1-4); all contain a JNK binding domain. JIP1 and JIP2 also contain SH3 and Phosphotyrosine-binding (PTB) domains. Both are highly expressed in the brain and pancreatic beta-cells. JIP1 functions as an adaptor linking motor to cargo during axonal transport and also is involved in regulating insulin secretion. JIP2 form complexes with fibroblast growth factor homologous factors (FHFs), which facilitates activation of the p38delta MAPK. The SH3 domain of JIP1 homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAYAVD 329
Cdd:cd11801   1 THRALHKFIPRHEDEIELDIGDPVYVEQEADDLWCEGTNLRTGQRGIFPAAYVVE 55

Src homology 3 domain of JNK-interacting protein 1; JNK-interacting protein 1 (JIP1) is also called Islet-brain 1 (IB1) or Mitogen-activated protein kinase 8-interacting protein 1 (MAPK8IP1). It is highly expressed in neurons, where it functions as an adaptor linking motor to cargo during axonal transport. It also affects microtubule dynamics in neurons. JIP1 is also found in pancreatic beta-cells, where it is involved in regulating insulin secretion. In addition to a JNK binding domain, JIP1 also contains SH3 and Phosphotyrosine-binding (PTB) domains. Its SH3 domain homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAYAVD 329
Cdd:cd11943   1 THRAVFRFVPRHPDELELEVDDPLLVEVQAEDYWYEAYNMRTGARGIFPAYYAIE 55

Src homology 3 domain of JNK-interacting protein 2; JNK-interacting protein 2 (JIP2) is also called Mitogen-activated protein kinase 8-interacting protein 2 (MAPK8IP2) or Islet-brain-2 (IB2). It is widely expressed in the brain, where it forms complexes with fibroblast growth factor homologous factors (FHFs), which facilitates activation of the p38delta MAPK. JIP2 is enriched in postsynaptic densities and may play a role in motor and cognitive function. In addition to a JNK binding domain, JIP2 also contains SH3 and Phosphotyrosine-binding (PTB) domains. The SH3 domain of the related protein JIP1 homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAYA 327
Cdd:cd11942   1 THRAVFRFIPRHEDELELDVDDPLLVEAEEDDYWYRGYNMRTGERGIFPAFYA 53

Tyrosine-specific kinase/HM-motif TK (TM/HMTK) Phosphotyrosine-binding (PTB) PH-like fold; TK kinases catalyzes the transfer of the terminal phosphate of ATP to a specific tyrosine residue on its target protein. TK kinases play significant roles in development and cell division. Tyrosine-protein kinases can be divided into two subfamilies: receptor tyrosine kinases, which have an intracellular tyrosine kinase domain, a transmembrane domain and an extracellular ligand-binding domain; and non-receptor (cytoplasmic) tyrosine kinases, which are soluble, cytoplasmic kinases. In HMTK the conserved His-Arg-Asp sequence within the catalytic loop is replaced by a His-Met sequence. TM/HMTK have are 2-3 N-terminal PTB domains. PTB domains in TKs are thought to function analogously to the membrane targeting (PH, myristoylation) and pTyr binding (SH2) domains of Src subgroup kinases. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains. This cd is part of the Dab-like subgroup.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632 351 YLGSVETLAHKGTGVVCQAVRKIvGEYGNSPTGQTciLEVSDQGLRMVDRsgpnqnkkDKKPCIDYFYsLKNVSFCAFHP 430
Cdd:cd13161   8 YLGSVPVKEPKGNDVVMAAVKRL-KDLKLKPKPVV--LVVSSEGIRVVER--------LTGEVLTNVP-IKDISFVTVDP 75

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*
gi 17979632 431 RDHRFIGFITKHPTVQRFACHVFKGSESTRPVAEAVGRAFQRFYQ 475
Cdd:cd13161  76 KDKKLFAFISHDPRLGRITCHVFRCKRGAQEICDTIAEAFKAAAE 120

Cell death protein 6 homolog (CED-6/GULP1) Phosphotyrosine-binding (PTB) domain; CED6 (also known as GULP1: engulfment adaptor PTB domain containing 1) is an adaptor protein involved in the specific recognition and engulfment of apoptotic cells. CED6 has been shown to interact with the cytoplasmic tail of another protein involved in the engulfment of apoptotic cells, CED1. CED6 has a C-terminal PTB domain, which can bind to NPXY motifs. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains. This cd is part of the Dab-like subgroup.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632 347 YLLGYLGSVETLAHKGTGVVCQAVRKI-----VGEYGNSPTgQTCILEVSDQGLRMVDrsgpnqnKKDKKpcIDYFYSLK 421
Cdd:cd01273  14 YLVKFLGCTEVEQPKGTEVVKEAIRKLkfarqLKKSEGAKL-PKVELQISIDGVKIQD-------PKTKV--IMHQFPLH 83

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 17979632 422 NVSFCAFHPRDHRFIGFITKHPTVQRFACHVFKGSESTRPVAEAVGRAFQRFYQKFIET 480
Cdd:cd01273  84 RISFCADDKTDKRIFSFIAKDSESEKHLCFVFDSEKLAEEITLTIGQAFDLAYRRFLES 142

Numb Phosphotyrosine-binding (PTB) domain; Numb is a membrane associated adaptor protein which plays critical roles in cell fate determination. Numb proteins are involved in control of asymmetric cell division and cell fate choice, endocytosis, cell adhesion, cell migration, ubiquitination of specific substrates and a number of signaling pathways (Notch, Hedgehog, p53). Mutations in Numb plays a critical role in disease (cancer). Numb has an N-terminal PTB domain and a C-terminal NumbF domain. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains. This cd is part of the Dab-like subgroup.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632 350 GYLGSVETLAHKGTGVVCQAVRKIVGEYGNSPTGqtcILEVSDQGLRMVDrsgpnqnKKDKKPCIDYfySLKNVSFCAFH 429
Cdd:cd01268  20 KYLGCVEVGESRGMQVCEEALKKLKASRKKPVRA---VLWVSGDGLRVVD-------EKTKGLIVDQ--TIEKVSFCAPD 87

                        90       100       110       120
                ....*....|....*....|....*....|....*....|...
gi 17979632 430 PRDHRFIGFITKHPTVQRFACHVFKGS-ESTRPVAEAVGRAFQ 471
Cdd:cd01268  88 RNHERAFSYICRDGTTRRWMCHCFLAVkDSGERLSHAVGCAFA 130

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 17979632    275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRtGRQGIFPSAY 326
Cdd:smart00326   4 QVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRLGR-GKEGLFPSNY 54

C-terminal (Fourth) Src Homology 3 domain of SH3 domain containing ring finger 1 (SH3RF1), SH3RF3, and similar domains; SH3RF1 (or POSH) and SH3RF3 (or POSH2) are scaffold proteins that function as E3 ubiquitin-protein ligases. They contain an N-terminal RING finger domain and four SH3 domains. This model represents the fourth SH3 domain, located at the C-terminus of SH3RF1 and SH3RF3, and similar domains. SH3RF1 plays a role in calcium homeostasis through the control of the ubiquitin domain protein Herp. It may also have a role in regulating death receptor mediated and JNK mediated apoptosis. SH3RF3 interacts with p21-activated kinase 2 (PAK2) and GTP-loaded Rac1. It may play a role in regulating JNK mediated apoptosis in certain conditions. 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
                ....*....|....*....|....*....|....*....|....
gi 17979632 284 PRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAYA 327
Cdd:cd11785  10 PQSEAELELKEGDIVFVHKKREDGWFKGTLQRTGKTGLFPGSFV 53

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        30        40        50
                ....*....|....*....|....*....|....*....|....*....|
gi 17979632 277 RGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRtGRQGIFPSAY 326
Cdd:cd00174   3 RALYDYEAQDDDELSFKKGDIITVLEKDDDGWWEGELNG-GREGLFPANY 51

Second Src Homology 3 domain (SH3B) of CD2-associated protein; CD2AP, also called CMS (Cas ligand with Multiple SH3 domains) or METS1 (Mesenchyme-to-Epithelium Transition protein with SH3 domains), is a cytosolic adaptor protein that plays a role in regulating the cytoskeleton. It is critical in cell-to-cell union necessary for kidney function. It also stabilizes the contact between a T cell and antigen-presenting cells. It is primarily expressed in podocytes at the cytoplasmic face of the slit diaphragm and serves as a linker anchoring podocin and nephrin to the actin cytoskeleton. CD2AP contains three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP to bind various protein partners and assemble complexes that have been implicated in many different functions. This alignment model represents the second SH3 domain (SH3B) of CD2AP. SH3B binds to c-Cbl in a site (TPSSRPLR is the core binding motif) distinct from the c-Cbl/SH3A binding site. 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 17979632 279 LHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNlrTGRQGIFPSAYAVDL 330
Cdd:cd12054   6 LFEYVPQNEDELELKVGDIIDINEEVEEGWWSGTL--NGKSGLFPSNFVKEL 55

Low Density Lipoprotein Receptor Adaptor Protein 1 (LDLRAP1) in mammals and similar proteins Phosphotyrosine-binding (PTB) PH-like fold; The null mutations in the LDL receptor adaptor protein 1 (LDLRAP1) gene, which serves as an adaptor for LDLR endocytosis in the liver, causes autosomal recessive hypercholesterolemia (ARH). LDLRAP1 contains a single PTB domain. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains. This cd contains mammals, insects, and sponges.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632 347 YLLGYLGS--VETLahKGTGVVCQAVRKIVGEYGNSPTG-QTCILEVSDQGLRMVDRSGpNQNKKDkkpcidyfYSLKNV 423
Cdd:cd13159   5 FYLKYLGStlVEKP--KGEGATAEAVKTIIAMAKASGKKlQKVTLTVSPKGIKVTDSAT-NETILE--------VSIYRI 73

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|..
gi 17979632 424 SFCAFHPRDHRFIGFITKHPTVQRFACHVFKGSEstRPVAEA----VGRAFQ 471
Cdd:cd13159  74 SYCTADANHDKVFAFIATNQDNEKLECHAFLCAK--RKMAQAvtltVAQAFN 123

Src homology 3 domain of Alpha1,6-fucosyltransferase (Fut8); Fut8 catalyzes the alpha1,6-linkage of a fucose residue from a donor substrate to N-linked oligosaccharides on glycoproteins in a process called core fucosylation, which is crucial for growth factor receptor-mediated biological functions. Fut8-deficient mice show severe growth retardation, early death, and a pulmonary emphysema-like phenotype. Fut8 is also implicated to play roles in aging and cancer metastasis. It contains an N-terminal coiled-coil domain, a catalytic domain, and a C-terminal SH3 domain. The SH3 domain of Fut8 is located in the lumen and its role in glycosyl transfer is unclear. 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
                ....*....|....*....|....*....|....*....|....*
gi 17979632 280 HKfvPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPS 324
Cdd:cd11792   8 HK--PRNHDEIELRVGDIIGVAGNHWDGYSKGRNRRTGKTGLYPS 50

Third (or C-terminal) Src Homology 3 domain of Vinexin, also called Sorbin and SH3 domain containing 3 (Sorbs3); Vinexin is also called Sorbs3, SH3P3, and SH3-containing adapter molecule 1 (SCAM-1). It is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. Vinexin was first identified as a vinculin binding protein; it is co-localized with vinculin at cell-ECM and cell-cell adhesion sites. There are several splice variants of vinexin: alpha, which contains the SoHo and three SH3 domains and displays tissue-specific expression; and beta, which contains only the three SH3 domains and is widely expressed. Vinexin alpha stimulates the accumulation of F-actin at focal contact sites. Vinexin also promotes keratinocyte migration and wound healing. The SH3 domains of vinexin have been reported to bind a number of ligands including vinculin, WAVE2, DLG5, Abl, and Cbl. 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 17979632 276 HRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11918   4 YKAVYQYRPQNEDELELREGDRVDVMQQCDDGWFVGVSRRTQKFGTFPGNY 54

Third Src Homology 3 domain of SH3 domain containing ring finger 3, an E3 ubiquitin-protein ligase; SH3RF3 is also called POSH2 (Plenty of SH3s 2) or SH3MD4 (SH3 multiple domains protein 4). It is a scaffold protein with E3 ubiquitin-protein ligase activity. It was identified in the screen for interacting partners of p21-activated kinase 2 (PAK2). It may play a role in regulating JNK mediated apoptosis in certain conditions. It also interacts with GTP-loaded Rac1. SH3RF3 is highly homologous to SH3RF1; it also contains an N-terminal RING finger domain and four SH3 domains. This model represents the third SH3 domain, located in the middle, of SH3RF3. 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
                ....*....|....*....|....*....|....*....|....*....
gi 17979632 278 GLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11925   5 ALYAYKPQKNDELELRKGEMYRVIEKCQDGWFKGTSLRTGVSGVFPGNY 53

Third Src Homology 3 domain of SH3 domain containing ring finger 1, an E3 ubiquitin-protein ligase; SH3RF1 is also called POSH (Plenty of SH3s) or SH3MD2 (SH3 multiple domains protein 2). It is a scaffold protein that acts as an E3 ubiquitin-protein ligase. It plays a role in calcium homeostasis through the control of the ubiquitin domain protein Herp. It may also have a role in regulating death receptor mediated and JNK mediated apoptosis. SH3RF1 also enhances the ubiquitination of ROMK1 potassium channel resulting in its increased endocytosis. It contains an N-terminal RING finger domain and four SH3 domains. This model represents the third SH3 domain, located in the middle, of SH3RF1. 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
                ....*....|....*....|....*....|....*....|....*....
gi 17979632 278 GLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11926   4 AIYPYTPRKEDELELRKGEMFLVFERCQDGWFKGTSMHTSKIGVFPGNY 52

Src homology 3 domain of Ubiquitin-associated and SH3 domain-containing protein A; UBASH3A is also called Cbl-Interacting Protein 4 (CLIP4), T cell Ubiquitin LigAnd (TULA), or T cell receptor Signaling (STS)-2. It is only found in lymphoid cells and exhibits weak phosphatase activity. UBASH3A facilitates T cell-induced apoptosis through interaction with the apoptosis-inducing factor AIF. It is involved in regulating the level of phosphorylation of the zeta-associated protein (ZAP)-70 tyrosine kinase. TULA proteins contain an N-terminal UBA domain, a central SH3 domain, and a C-terminal histidine phosphatase domain. They bind c-Cbl through the SH3 domain and to ubiquitin via UBA. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYV----QKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11937   2 TLRALFQYKPQNIDELMLSPGDYIFVdptqQSEASEGWVIGISHRTGCRGFLPENY 57

Tensin Phosphotyrosine-binding (PTB) domain; Tensin is a a focal adhesion protein, which contains a C-terminal SH2 domain followed by a PTB domain. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains. This cd is part of the Dab-like subgroup.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632 351 YLGSV--ETLahkgTGVvcQAVRKIVGEY-GNSPTGQTCI--LEVSDQGLRMVDrsgpNQNKKdkkpcidYF---YSLKN 422
Cdd:cd01213   8 YLGSVdtESL----TGP--QAVRKAVSETlERDPLPTPTVvhFKVSEQGITLTD----NQRKL-------FFrrhYPLNT 70

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*
gi 17979632 423 VSFCAFHPRDHRF-------------IGFITKHPTV-QRFACHVF 453
Cdd:cd01213  71 VSFCGMDPENRKWqkydlrgskpsriFGFVARKQGSsTENVCHLF 115

Third (or C-terminal) Src Homology 3 domain of Sorbin and SH3 domain containing 2 (Sorbs2), also called Arg-binding protein 2 (ArgBP2); Sorbs2 or ArgBP2 is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. It regulates actin-dependent processes including cell adhesion, morphology, and migration. It is expressed in many tissues and is abundant in the heart. Like vinexin, it is found in focal adhesion where it interacts with vinculin and afadin. It also localizes in epithelial cell stress fibers and in cardiac muscle cell Z-discs. Sorbs2 has been implicated to play roles in the signaling of c-Arg, Akt, and Pyk2. Other interaction partners of Sorbs2 include c-Abl, flotillin, spectrin, dynamin 1/2, synaptojanin, PTP-PEST, among others. 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 17979632 276 HRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11917   7 FQALYNYMPRNEDELELREGDVIDVMEKCDDGWFVGTSRRTKFFGTFPGNY 57

Src homology 3 domain of Abl Interactor proteins; Abl interactor (Abi) proteins are adaptor proteins serving as binding partners and substrates of Abl tyrosine kinases. They are involved in regulating actin cytoskeletal reorganization and play important roles in membrane-ruffling, endocytosis, cell motility, and cell migration. They localize to sites of actin polymerization in epithelial adherens junction and immune synapses, as well as to the leading edge of lamellipodia. Vertebrates contain two Abi proteins, Abi1 and Abi2. Abi1 displays a wide expression pattern while Abi2 is highly expressed in the eye and brain. Abi proteins contain a homeobox homology domain, a proline-rich region, and a SH3 domain. The SH3 domain of Abi binds to a PxxP motif in Abl. 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
                ....*....|....*....|....*....|....*....
gi 17979632 288 DEIELEIGDAIYVQKEAEDLWCEGVnlRTGRQGIFPSAY 326
Cdd:cd11826  14 DELSFQEGDIIYVTKKNDDGWYEGV--LNGVTGLFPGNY 50

Src Homology 3 domain of fungal BOI-like proteins; This subfamily includes the Saccharomyces cerevisiae proteins BOI1 and BOI2, and similar proteins. They contain an N-terminal SH3 domain, a Sterile alpha motif (SAM), and a Pleckstrin homology (PH) domain at the C-terminus. BOI1 and BOI2 interact with the SH3 domain of Bem1p, a protein involved in bud formation. They promote polarized cell growth and participates in the NoCut signaling pathway, which is involved in the control of cytokinesis. SH3 domains bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs; they play a role in the regulation of enzymes by intramolecular interactions, changing the subcellular localization of signal pathway components and mediate multiprotein complex assemblies.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|.
gi 17979632 279 LHKFVPRHHDEIELEIGDAIYVQKEAE---DLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11886   5 IHDFNARSEDELTLKPGDKIELIEDDEefgDGWYLGRNLRTGETGLFPVVF 55

First C-terminal Src homology 3 domain of SH3 and cysteine-rich domain-containing (Stac) proteins; Stac proteins are putative adaptor proteins that contain a cysteine-rich C1 domain and one or two SH3 domains at the C-terminus. There are three mammalian members (Stac1, Stac2, and Stac3) of this family. Stac1 and Stac3 contain two SH3 domains while Stac2 contains a single SH3 domain at the C-terminus. This model represents the first C-terminal SH3 domain of Stac1 and Stac3, and the single C-terminal SH3 domain of Stac2. Stac1 and Stac2 have been found to be expressed differently in mature dorsal root ganglia (DRG) neurons. Stac1 is mainly expressed in peptidergic neurons while Stac2 is found in a subset of nonpeptidergic and all trkB+ neurons. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVnlRTGRQGIFPSAYA 327
Cdd:cd11833   1 TYVALYKFKPQENEDLEMRPGDKITLLDDSNEDWWKGK--IEDRVGFFPANFV 51

Family with sequence similarity 43, member A (FAM43A) Phosphotyrosine-binding (PTB) domain; The function of FAM43A is currently unknown. Human FAM43A is located on chromosome 3 at location 3q29. It encodes a 3182 base pair mRNA which possesses one Pleckstrin homology-like domain. The mRNA translates into LOC131583, a hydrophilic protein that is predicted to localize in the nucleus. The FAM43A gene is conserved through a broad range of vertebrates. It is highly conserved from chimpanzees to zebrafish. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632 333 NEFDPTvqlvkkerYLLGYLGSVETLAHKGTGVVCQAVRKIVGEYGNSPTGQTCI-LEVSDQGLRMVDRSGPNQnkkdkk 411
Cdd:cd01214   2 TEEDPT--------YTVVYLGNVLTIWAKGEGCTDKPLATIWRNYTQGKKPDVKMkLTVTPSGLKATTKQHGLT------ 67

                        90       100       110       120
                ....*....|....*....|....*....|....*....|...
gi 17979632 412 pcidyFYSLKNVSFCAFHPRDHRFIGFITKHPT---VQRFACH 451
Cdd:cd01214  68 -----EYWLHRITYCSAPPNYPRVFCWIYRHEGrklKVELRCH 105

Src Homology 3 domain of Amphiphysin and related domains; Amphiphysins function primarily in endocytosis and other membrane remodeling events. They exist in several isoforms and mammals possess two amphiphysin proteins from distinct genes. Amphiphysin I proteins, enriched in the brain and nervous system, contain domains that bind clathrin, Adaptor Protein complex 2 (AP2), dynamin, and synaptojanin. They function in synaptic vesicle endocytosis. Human autoantibodies to amphiphysin I hinder GABAergic signaling and contribute to the pathogenesis of paraneoplastic stiff-person syndrome. Some amphiphysin II isoforms, also called Bridging integrator 1 (Bin1), are localized in many different tissues and may function in intracellular vesicle trafficking. In skeletal muscle, Bin1 plays a role in the organization and maintenance of the T-tubule network. Mutations in Bin1 are associated with autosomal recessive centronuclear myopathy. Amphiphysins contain an N-terminal BAR domain with an additional N-terminal amphipathic helix (an N-BAR), a variable central domain, and a C-terminal SH3 domain. The SH3 domain of amphiphysins bind proline-rich motifs present in binding partners such as dynamin, synaptojanin, and nsP3. It also belongs to a subset of SH3 domains that bind ubiquitin in a site that overlaps with the peptide binding site. 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 17979632 277 RGLHKFVPRHHDEIELEIGDAIYV-----QKEAEDLWCEGVNLRTGRQGIFP 323
Cdd:cd11790   6 RATHDYTAEDTDELTFEKGDVILVipfddPEEQDEGWLMGVKESTGCRGVFP 57

First Src homology 3 domain (or SH3A) of Intersectin-1; Intersectin-1 (ITSN1) is an adaptor protein that functions in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. It plays a role in clathrin-coated pit (CCP) formation. It binds to many proteins through its multidomain structure and facilitate the assembly of multimeric complexes. ITSN1 localizes in membranous organelles, CCPs, the Golgi complex, and may be involved in the cell membrane trafficking system. It exists in alternatively spliced short and long isoforms. The short isoform contains two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoform, in addition, contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. The first SH3 domain (or SH3A) of ITSN1 has been shown to bind many proteins including Sos1, dynamin1/2, CIN85, c-Cbl, PI3K-C2, SHIP2, N-WASP, and CdGAP, among others. 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 17979632 276 HRGLHKFVPRHHDEIELEIGDAIYVQKE--AEDLWCEGvNLRtGRQGIFPSAYA 327
Cdd:cd11987   2 YRALYPFEARSHDEITIQPGDIVMVDESqtGEPGWLGG-ELK-GKTGWFPANYA 53

Third N-terminal Src homology 3 domain of Dynamin Binding Protein, also called Tuba; DNMBP or Tuba is a cdc42-specific guanine nucleotide exchange factor (GEF) that contains four N-terminal SH3 domains, a central RhoGEF [or Dbl homology (DH)] domain followed by a Bin/Amphiphysin/Rvs (BAR) domain, and two C-terminal SH3 domains. It provides a functional link between dynamin and key regulatory proteins of the actin cytoskeleton. It plays an important role in regulating cell junction configuration. The four N-terminal SH3 domains of DNMBP binds the GTPase dynamin, which plays an important role in the fission of endocytic vesicles. 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
                ....*....|....*....|....*....|....*....
gi 17979632 288 DEIELEIGDAIYVQKEAEDLWCEGVNlrTGRQGIFPSAY 326
Cdd:cd11796  14 EELDLREGDVVTITGILDKGWFRGEL--NGRRGIFPEGF 50

Fourth Src homology 3 domain of ADAM-binding protein Eve-1; Eve-1, also called SH3 domain-containing protein 19 (SH3D19) or EEN-binding protein (EBP), exists in multiple alternatively spliced isoforms. The longest isoform contains five SH3 domain in the C-terminal region and seven proline-rich motifs in the N-terminal region. It is abundantly expressed in skeletal muscle and heart, and may be involved in regulating the activity of ADAMs (A disintegrin and metalloproteases). Eve-1 interacts with EEN, an endophilin involved in endocytosis and may be the target of the MLL-EEN fusion protein that is implicated in leukemogenesis. 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
                ....*....|....*....|....*....|....*....|....*....
gi 17979632 279 LHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEG-VNlrtGRQGIFPSAY 326
Cdd:cd11817   5 LYDFTGETEEDLSFQRGDRILVTEHLDAEWSRGrLN---GREGIFPRAF 50

C-terminal Src Homology 3 domain of the Nebulin family of proteins; Nebulin family proteins contain multiple nebulin repeats, and may contain an N-terminal LIM domain and/or a C-terminal SH3 domain. They have molecular weights ranging from 34 to 900 kD, depending on the number of nebulin repeats, and they all bind actin. They are involved in the regulation of actin filament architecture and function as stabilizers and scaffolds for cytoskeletal structures with which they associate, such as long actin filaments or focal adhesions. Nebulin family proteins that contain a C-terminal SH3 domain include the giant filamentous protein nebulin, nebulette, Lasp1, and Lasp2. Lasp2, also called LIM-nebulette, is an alternatively spliced variant of nebulette. 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
                ....*....|....*....|....*....|....*....
gi 17979632 288 DEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11789  14 DEVSFQEGDVIINVEIIDDGWMEGTVQRTGQSGMLPANY 52

Fe65 C-terminal Phosphotyrosine-binding (PTB) domain; The neuronal adaptor protein Fe65 is involved in brain development, Alzheimer disease amyloid precursor protein (APP) signaling, and proteolytic processing of APP. It contains three protein-protein interaction domains, one WW domain, and a unique tandem array of phosphotyrosine-binding (PTB) domains. The C-terminal PTB domain is responsible for APP binding. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains. This cd is part of the Dab-like subgroup.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....
gi 17979632 423 VSFCAFHPRDHRFiGFITkHPTVQRFACHVFKGSESTRPVAEAVGRAFQRFYQK 476
Cdd:cd01271  76 LSFMGIGKDVHTF-AFIM-DTGPQLFQCHVFWCEPNAGALSEAVQAACMLRYQK 127

Src Homology 3 domain of metazoan osteoclast stimulating factor 1; OSTF1, also named OSF or SH3P2, is a signaling protein containing SH3 and ankyrin-repeat domains. It acts through a Src-related pathway to enhance the formation of osteoclasts and bone resorption. It also acts as a negative regulator of cell motility. 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 17979632 277 RGLHKFVPRHHDEIELEIGDAIYVQKEAEDLW----CEgvnlrtGRQGIFPSAY 326
Cdd:cd11772   3 RALYDYEAQHPDELSFEEGDLLYISDKSDPNWwkatCG------GKTGLIPSNY 50

Src homology 3 domain of the Rho guanine nucleotide exchange factor, ephexin-1 (also called NGEF or ARHGEF27); Ephexin-1, also called NGEF (neuronal GEF) or ARHGEF27, activates RhoA, Tac1, and Cdc42 by exchanging bound GDP for free GTP. It is expressed mainly in the brain in a region associated with movement control. It regulates the stability of postsynaptic acetylcholine receptor (AChR) clusters and thus, plays a critical role in the maturation and neurotransmission of neuromuscular junctions. Ephexin-1 directly interacts with the ephrin receptor EphA4 and their coexpression enhances the ability of ephexin-1 to activate RhoA. It is required for normal axon growth and EphA-induced growth cone collapse. Ephexin-1 contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), and SH3 domains. The SH3 domains of ARHGEFs play an autoinhibitory role through intramolecular interactions with a proline-rich region N-terminal to the DH domain. 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
                ....*....|....*....|....*....|....*....|....*.
gi 17979632 279 LHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPS 324
Cdd:cd11939   5 VHPYVSQEPDELSLELADVLNILDKTDDGWIFGERLHDQERGWFPS 50

Src Homology 3 domain of Insulin Receptor tyrosine kinase Substrate p53, Brain-specific Angiogenesis Inhibitor 1-Associated Protein 2 (BAIAP2)-Like proteins, and similar proteins; Proteins in this family include IRSp53, BAIAP2L1, BAIAP2L2, and similar proteins. They all contain an Inverse-Bin/Amphiphysin/Rvs (I-BAR) or IMD domain in addition to the SH3 domain. IRSp53, also known as BAIAP2, is a scaffolding protein that takes part in many signaling pathways including Cdc42-induced filopodia formation, Rac-mediated lamellipodia extension, and spine morphogenesis. IRSp53 exists as multiple splicing variants that differ mainly at the C-termini. BAIAP2L1, also called IRTKS (Insulin Receptor Tyrosine Kinase Substrate), serves as a substrate for the insulin receptor and binds the small GTPase Rac. It plays a role in regulating the actin cytoskeleton and colocalizes with F-actin, cortactin, VASP, and vinculin. IRSp53 and IRTKS also mediate the recruitment of effector proteins Tir and EspFu, which regulate host cell actin reorganization, to bacterial attachment sites. BAIAP2L2 co-localizes with clathrin plaques but its function has not been determined. The SH3 domains of IRSp53 and IRTKS have been shown to bind the proline-rich C-terminus of EspFu. 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 17979632 277 RGLHKFVPRHHDEIELEIGDAI-YVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11779   4 KALYPHAAGGETQLSFEEGDVItLLGPEPRDGWHYGENERSGRRGWFPIAY 54

Second Src Homology 3 domain of Sorbin and SH3 domain containing 2 (Sorbs2), also called Arg-binding protein 2 (ArgBP2); Sorbs2 or ArgBP2 is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. It regulates actin-dependent processes including cell adhesion, morphology, and migration. It is expressed in many tissues and is abundant in the heart. Like vinexin, it is found in focal adhesion where it interacts with vinculin and afadin. It also localizes in epithelial cell stress fibers and in cardiac muscle cell Z-discs. Sorbs2 has been implicated to play roles in the signaling of c-Arg, Akt, and Pyk2. Other interaction partners of Sorbs2 include c-Abl, flotillin, spectrin, dynamin 1/2, synaptojanin, PTP-PEST, among others. 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
                ....*....|....*....|....*....|....*...
gi 17979632 289 EIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11923  16 ELSLRKGDRVVLLKQVDQNWYEGKIPGTNRQGIFPVSY 53

Phosphotyrosine-binding domain; The phosphotyrosine-binding domain (PTB, also phosphotyrosine-interaction or PI domain) in the protein tensin tends to be found at the C-terminus. Tensin is a multi-domain protein that binds to actin filaments and functions as a focal-adhesion molecule (focal adhesions are regions of plasma membrane through which cells attach to the extracellular matrix). Human tensin has actin-binding sites, an SH2 (pfam00017) domain and a region similar to the tumour suppressor PTEN. The PTB domain interacts with the cytoplasmic tails of beta integrin by binding to an NPXY motif.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17979632   381 PTGQTCILEVSDQGLRMVDrsgpNQNKKDKKPcidyfYSLKNVSFCAFHPRDHRFI---GFITKHPTVQRFACHVFKGSE 457
Cdd:pfam08416  37 VWTQEMLLQVSDQGITLTD----NETKEELES-----YPLDSISHCQAVLNDGRYNsilALVCQEPGQSKPDVHLFQCDE 107

                          90       100
                  ....*....|....*....|...
gi 17979632   458 STrpvAEAVGRAFQRFYQKFIET 480
Cdd:pfam08416 108 LG---AELIAEDIESALSDVRLG 127

C-terminal Src Homology 3 domain of Nebulin; Nebulin is a giant filamentous protein (600-900 kD) that is expressed abundantly in skeletal muscle. It binds to actin thin filaments and regulates its assembly and function. Nebulin was thought to be part of a molecular ruler complex that is critical in determining the lengths of actin thin filaments in skeletal muscle since its length, which varies due to alternative splicing, correlates with the length of thin filaments in various muscle types. Recent studies indicate that nebulin regulates thin filament length by stabilizing the filaments and preventing depolymerization. Mutations in nebulin can cause nemaline myopathy, characterized by muscle weakness which can be severe and can lead to neonatal lethality. Nebulin contains an N-terminal LIM domain, many nebulin repeats/super repeats, and a C-terminal SH3 domain. 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 17979632 275 THRGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNLRTGRQGIFPSAY 326
Cdd:cd11933   3 SFRAMYDYRAADDDEVSFKDGDTIVNVQTIDEGWMYGTVQRTGKTGMLPANY 54

Src homology 3 domain of Cortactin and related proteins; This subfamily includes cortactin, Abp1 (actin-binding protein 1), hematopoietic lineage cell-specific protein 1 (HS1), and similar proteins. These proteins are involved in regulating actin dynamics through direct or indirect interaction with the Arp2/3 complex, which is required to initiate actin polymerization. They all contain at least one C-terminal SH3 domain. Cortactin and HS1 bind Arp2/3 and actin through an N-terminal region that contains an acidic domain and several copies of a repeat domain found in cortactin and HS1. Abp1 binds actin via an N-terminal actin-depolymerizing factor (ADF) homology domain. Yeast Abp1 binds Arp2/3 directly through two acidic domains. Mammalian Abp1 does not directly interact with Arp2/3; instead, it regulates actin dynamics indirectly by interacting with dynamin and WASP family proteins. The C-terminal region of these proteins acts as an adaptor or scaffold that can connect membrane trafficking and signaling proteins that bind the SH3 domain within the actin network. 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 17979632 277 RGLHKFVPRHHDEIELEIGDAIYVQKEAEDLWCEGVNlRTGRQGIFPSAY 326
Cdd:cd11819   3 KALYDYQAAEDNEISFVEGDIITQIEQIDEGWWLGVN-AKGQKGLFPANY 51