N-terminal Src homology 2 (nSH2) domain found in p85; Phosphoinositide 3-kinases (PI3Ks) are essential for cell growth, migration, and survival. p110, the catalytic subunit, is composed of an adaptor-binding domain, a Ras-binding domain, a C2 domain, a helical domain, and a kinase domain. The regulatory unit is called p85 and is composed of an SH3 domain, a RhoGap domain, a N-terminal SH2 (nSH2) domain, an internal SH2 (iSH2) domain, and C-terminal (cSH2) domain. There are 2 inhibitory interactions between p110alpha and p85 of P13K: (1) p85 nSH2 domain with the C2, helical, and kinase domains of p110alpha and (2) p85 iSH2 domain with C2 domain of p110alpha. There are 3 inhibitory interactions between p110beta and p85 of P13K: (1) p85 nSH2 domain with the C2, helical, and kinase domains of p110beta, (2) p85 iSH2 domain with C2 domain of p110alpha, and (3) p85 cSH2 domain with the kinase domain of p110alpha. It is interesting to note that p110beta is oncogenic as a wild type protein while p110alpha lacks this ability. One explanation is the idea that the regulation of p110beta by p85 is unique because of the addition of inhibitory contacts from the cSH2 domain and the loss of contacts in the iSH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  59 SLQDAEWYWGDISREEVNDKLRDMPDGTFLVRDASTkMQGDYTLTLRKGGNNKLIKIYHRDGKYGFSEPLTFTSVVELIN 138
Cdd:cd09942    3 SLQEAEWYWGDISREEVNEKMRDTPDGTFLVRDAST-MKGDYTLTLRKGGNNKLIKIFHRDGKYGFSDPLTFNSVVELIN 81

                         90       100
                 ....*....|....*....|....*....
gi 568928613 139 HYHHESLAQYNPKLDVKLTYPVSRFQQDQ 167
Cdd:cd09942   82 YYRNNSLAEYNRKLDVKLLYPVSRFQQDQ 110

Phosphatidylinositol 3-kinase regulatory subunit P85 inter-SH2 domain; This domain is found between the two SH2 domains in phosphatidylinositol 3-kinase regulatory subunit P85. It forms a complex with the adaptor-binding domain of phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  163 FQQDQLVKEDNIDAVGKNLQEFHSQYQEKSKEYDRLYEEYTRTSQEIQMKRTAIEAFNETIKIFEEQCHTQEqhskdyie 242
Cdd:pfam16454   1 QQEDEVVKEDDIEAVGKKLIEIHKQYLEKSREYDRLYEEYNKTSQEIQMKRQALEAFNEAIKMFEEQIKLQE-------- 72

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  243 RFRREGNEKEIERIMMNYDKLKSRLGEIHDSKLRLEQDLKKQALDNREIDKKMNSIKPDLIQLRKIRDQHLVWLNHRGVR 322
Cdd:pfam16454  73 RFSKEAQPHEIERLLENYELLKSRLKELHDSKEQLEEDLKTQKEYNRELEREMNSLKPELIQLRKQKDQYLEWLKRKGVT 152

                  ....*....
gi 568928613  323 QRRLNAWLG 331
Cdd:pfam16454 153 QEQINAWLG 161

Src homology 2 domains; Src homology 2 domains bind phosphotyrosine-containing polypeptides via 2 surface pockets. Specificity is provided via interaction with residues that are distinct from the phosphotyrosine. Only a single occurrence of a SH2 domain has been found in S. cerevisiae.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613    64 EWYWGDISREEVNDKLRDMPDGTFLVRDaSTKMQGDYTLTLRKGGNNKLIKIYH-RDGKYGFSEPLTFTSVVELINHYHH 142
Cdd:smart00252   2 PWYHGFISREEAEKLLKNEGDGDFLVRD-SESSPGDYVLSVRVKGKVKHYRIRRnEDGKFYLEGGRKFPSLVELVEHYQK 80

                   ...
gi 568928613   143 ESL 145
Cdd:smart00252  81 NSL 83

SH2 domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 568928613   65 WYWGDISREEVNDKLR-DMPDGTFLVRDASTKmQGDYTLTLRKGGNNKLIKI-YHRDGKYGFSEPLTFTSVVELINHY 140
Cdd:pfam00017   1 WYHGKISRQEAERLLLnGKPDGTFLVRESEST-PGGYTLSVRDDGKVKHYKIqSTDNGGYYISGGVKFSSLAELVEHY 77

Src homology 2 domains; Src homology 2 domains bind phosphotyrosine-containing polypeptides via 2 surface pockets. Specificity is provided via interaction with residues that are distinct from the phosphotyrosine. Only a single occurrence of a SH2 domain has been found in S. cerevisiae.

                           10        20        30
                   ....*....|....*....|....*....|....*....
gi 568928613   358 WFVEDINRVQAEDLLYGKPDGAFLIRES-SKKGCYACSV 395
Cdd:smart00252   3 WYHGFISREEAEKLLKNEGDGDFLVRDSeSSPGDYVLSV 41

chromosome segregation protein SMC, common bacterial type; SMC (structural maintenance of chromosomes) proteins bind DNA and act in organizing and segregating chromosomes for partition. SMC proteins are found in bacteria, archaea, and eukaryotes. This family represents the SMC protein of most bacteria. The smc gene is often associated with scpB (TIGR00281) and scpA genes, where scp stands for segregation and condensation protein. SMC was shown (in Caulobacter crescentus) to be induced early in S phase but present and bound to DNA throughout the cell cycle. [Cellular processes, Cell division, DNA metabolism, Chromosome-associated proteins]

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613   182 QEFHSQYQEKSKEYDRLYEEYTRTSQEIQMKRTAIEAFNETIKIFEEQCHTQEQHSKDYIERFRRegNEKEIERIMMNYD 261
Cdd:TIGR02168  277 SELEEEIEELQKELYALANEISRLEQQKQILRERLANLERQLEELEAQLEELESKLDELAEELAE--LEEKLEELKEELE 354

                           90       100       110       120
                   ....*....|....*....|....*....|....*....|....*.
gi 568928613   262 KLKSRLgeihDSKLRLEQDLKKQaldNREIDKKMNSIKPDLIQLRK 307
Cdd:TIGR02168  355 SLEAEL----EELEAELEELESR---LEELEEQLETLRSKVAQLEL 393

Inter-Src homology 2 (iSH2) helical domain of Class IA Phosphoinositide 3-kinase Regulatory subunit 2, PIK3R2, also called p85beta; PI3Ks catalyze the transfer of the gamma-phosphoryl group from ATP to the 3-hydroxyl of the inositol ring of D-myo-phosphatidylinositol (PtdIns) or its derivatives. They play an important role in a variety of fundamental cellular processes, including cell motility, the Ras pathway, vesicle trafficking and secretion, immune cell activation, and apoptosis. They are classified according to their substrate specificity, regulation, and domain structure. Class IA PI3Ks are heterodimers of a p110 catalytic (C) subunit and a p85-related regulatory (R) subunit. The R subunit down-regulates PI3K basal activity, stabilizes the C subunit, and plays a role in the activation downstream of tyrosine kinases. All R subunits contain two SH2 domains that flank an intervening helical domain (iSH2), which binds to the N-terminal adaptor-binding domain (ABD) of the catalytic subunit. p85beta, also called PIK3R2, contains N-terminal SH3 and GAP domains. It is expressed ubiquitously but at lower levels than p85alpha. Its expression is increased in breast and colon cancer, correlates with tumor progression, and enhanced invasion. During viral infection, the viral nonstructural (NS1) protein binds p85beta specifically, which leads to PI3K activation and the promotion of viral replication. Mice deficient with PIK3R2 develop normally and exhibit moderate metabolic and immunological defects.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613 172 DNIDAVGKNLQEFHSQYQEKSKEYDRLYEEYTRTSQEIQMKRTAIEAFNETIKIFEEQCHTQEQHSKDYIERFRREGNEK 251
Cdd:cd12926    1 DSVEAVGAQLKVYHQQYQDKSREYDQLYEEYTRTSQELQMKRTAIEAFNETIKIFEEQGQTQEKCSKEYLERFRREGNEK 80

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613 252 EIERIMMNYDKLKSRLGEIHDSKLRLEQDLKKQALDNREIDKKMNSIKPDLIQLRKIRDQHLVWLNHRGVRQRRLNAWLG 331
Cdd:cd12926   81 EMQRILLNSERLKSRIAEIHESRTKLEQDLRAQASDNREIDKRMNSLKPDLMQLRKIRDQYLVWLTQKGARQKKINEWLG 160

                 .
gi 568928613 332 I 332
Cdd:cd12926  161 I 161

Phosphatidylinositol 3-kinase regulatory subunit P85 inter-SH2 domain; This domain is found between the two SH2 domains in phosphatidylinositol 3-kinase regulatory subunit P85. It forms a complex with the adaptor-binding domain of phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  163 FQQDQLVKEDNIDAVGKNLQEFHSQYQEKSKEYDRLYEEYTRTSQEIQMKRTAIEAFNETIKIFEEQCHTQEqhskdyie 242
Cdd:pfam16454   1 QQEDEVVKEDDIEAVGKKLIEIHKQYLEKSREYDRLYEEYNKTSQEIQMKRQALEAFNEAIKMFEEQIKLQE-------- 72

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  243 RFRREGNEKEIERIMMNYDKLKSRLGEIHDSKLRLEQDLKKQALDNREIDKKMNSIKPDLIQLRKIRDQHLVWLNHRGVR 322
Cdd:pfam16454  73 RFSKEAQPHEIERLLENYELLKSRLKELHDSKEQLEEDLKTQKEYNRELEREMNSLKPELIQLRKQKDQYLEWLKRKGVT 152

                  ....*....
gi 568928613  323 QRRLNAWLG 331
Cdd:pfam16454 153 QEQINAWLG 161

Inter-Src homology 2 (iSH2) helical domain of Class IA Phosphoinositide 3-kinase Regulatory subunits; PI3Ks catalyze the transfer of the gamma-phosphoryl group from ATP to the 3-hydroxyl of the inositol ring of D-myo-phosphatidylinositol (PtdIns) or its derivatives. They play an important role in a variety of fundamental cellular processes, including cell motility, the Ras pathway, vesicle trafficking and secretion, immune cell activation, and apoptosis. They are classified according to their substrate specificity, regulation, and domain structure. Class IA PI3Ks are heterodimers of a p110 catalytic (C) subunit and a p85-related regulatory (R) subunit. The R subunit down-regulates PI3K basal activity, stabilizes the C subunit, and plays a role in the activation downstream of tyrosine kinases. All R subunits contain two SH2 domains that flank an intervening helical domain (iSH2), which binds to the N-terminal adaptor-binding domain (ABD) of the catalytic subunit. In vertebrates, there are three genes (PIK3R1, PIK3R2, and PIK3R3) that encode for different Class IA PI3K R subunits.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613 172 DNIDAVGKNLQEFHSQYQEKSKEYDRLYEEYTRTSQEIQMKRTAIEAFNETIKIFEEQCHTQEQHSKDYierfrregNEK 251
Cdd:cd12923    1 DDVEKLAKKLKEINKEYLDKSREYDELYEKYNKLSQEIQLKRQALEAFEEAVKMFEEQLRTQEKFQKEA--------QPH 72

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613 252 EIERIMMNYDKLKSRLGEIHDSKLRLEQDLKKQALDNREIDKKMNSIKPDLIQLRKIRDQHLVWLNHRGVRQRRLNAWLG 331
Cdd:cd12923   73 EKQRLMENNELLKSRLKELEESKEQLEEDLRKQVAYNRELEREMNSLKPELMQLRKQKDQYLRWLKRKGVSQEEINQLLK 152

C-terminal Src homology 2 (cSH2) domain found in p85; Phosphoinositide 3-kinases (PI3Ks) are essential for cell growth, migration, and survival. p110, the catalytic subunit, is composed of an adaptor-binding domain, a Ras-binding domain, a C2 domain, a helical domain, and a kinase domain. The regulatory unit is called p85 and is composed of an SH3 domain, a RhoGap domain, a N-terminal SH2 (nSH2) domain, a inter SH2 (iSH2) domain, and C-terminal (cSH2) domain. There are 2 inhibitory interactions between p110alpha and p85 of P13K: 1) p85 nSH2 domain with the C2, helical, and kinase domains of p110alpha and 2) p85 iSH2 domain with C2 domain of p110alpha. There are 3 inhibitory interactions between p110beta and p85 of P13K: 1) p85 nSH2 domain with the C2, helical, and kinase domains of p110beta, 2) p85 iSH2 domain with C2 domain of p110alpha, and 3) p85 cSH2 domain with the kinase domain of p110alpha. It is interesting to note that p110beta is oncogenic as a wild type protein while p110alpha lacks this ability. One explanation is the idea that the regulation of p110beta by p85 is unique because of the addition of inhibitory contacts from the cSH2 domain and the loss of contacts in the iSH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 568928613 351 PHYDEKTWFVEDINRVQAEDLLYGKPDGAFLIRESSKKGCYACSVV 396
Cdd:cd09930    1 PHHDERTWLVGDINRTQAEELLRGKPDGTFLIRESSTQGCYACSVV 46

C-terminal Src homology 2 (cSH2) domain found in p85; Phosphoinositide 3-kinases (PI3Ks) are essential for cell growth, migration, and survival. p110, the catalytic subunit, is composed of an adaptor-binding domain, a Ras-binding domain, a C2 domain, a helical domain, and a kinase domain. The regulatory unit is called p85 and is composed of an SH3 domain, a RhoGap domain, a N-terminal SH2 (nSH2) domain, a inter SH2 (iSH2) domain, and C-terminal (cSH2) domain. There are 2 inhibitory interactions between p110alpha and p85 of P13K: 1) p85 nSH2 domain with the C2, helical, and kinase domains of p110alpha and 2) p85 iSH2 domain with C2 domain of p110alpha. There are 3 inhibitory interactions between p110beta and p85 of P13K: 1) p85 nSH2 domain with the C2, helical, and kinase domains of p110beta, 2) p85 iSH2 domain with C2 domain of p110alpha, and 3) p85 cSH2 domain with the kinase domain of p110alpha. It is interesting to note that p110beta is oncogenic as a wild type protein while p110alpha lacks this ability. One explanation is the idea that the regulation of p110beta by p85 is unique because of the addition of inhibitory contacts from the cSH2 domain and the loss of contacts in the iSH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  65 WYWGDISREEVNDKLRDMPDGTFLVRDASTkmQGDYTLTLRKGGNNKLIKIYHRDGKYGFSEPLT-FTSVVELINHYHHE 143
Cdd:cd09930    8 WLVGDINRTQAEELLRGKPDGTFLIRESST--QGCYACSVVCNGEVKHCVIYKTETGYGFAEPYNlYESLKELVLHYAHN 85

                         90
                 ....*....|....*..
gi 568928613 144 SLAQYNPKLDVKLTYPV 160
Cdd:cd09930   86 SLEQHNDSLTVTLAYPV 102

Src homology 2 (SH2) domain found in the Vav family; Vav proteins are involved in several processes that require cytoskeletal reorganization, such as the formation of the immunological synapse (IS), phagocytosis, platelet aggregation, spreading, and transformation. Vavs function as guanine nucleotide exchange factors (GEFs) for the Rho/Rac family of GTPases. Vav family members have several conserved motifs/domains including: a leucine-rich region, a leucine-zipper, a calponin homology (CH) domain, an acidic domain, a Dbl-homology (DH) domain, a pleckstrin homology (PH) domain, a cysteine-rich domain, 2 SH3 domains, a proline-rich region, and a SH2 domain. Vavs are the only known Rho GEFs that have both the DH/PH motifs and SH2/SH3 domains in the same protein. The leucine-rich helix-loop-helix (HLH) domain is thought to be involved in protein heterodimerization with other HLH proteins and it may function as a negative regulator by forming inactive heterodimers. The CH domain is usually involved in the association with filamentous actin, but in Vav it controls NFAT stimulation, Ca2+ mobilization, and its transforming activity. Acidic domains are involved in protein-protein interactions and contain regulatory tyrosines. The DH domain is a GDP-GTP exchange factor on Rho/Rac GTPases. The PH domain in involved in interactions with GTP-binding proteins, lipids and/or phosphorylated serine/threonine residues. The SH3 domain is involved in localization of proteins to specific sites within the cell interacting with protein with proline-rich sequences. The SH2 domain mediates a high affinity interaction with tyrosine phosphorylated proteins. There are three Vav mammalian family members: Vav1 which is expressed in the hematopoietic system, Vav2 and Vav3 are more ubiquitously expressed. The members here include insect and amphibian Vavs. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  64 EWYWGDISREEVNDKLRDMPDGTFLVRdASTKMQGDYTLTLRKGGNNKLIKIYHR-DGKYGFSEPLTFTSVVELINHYHH 142
Cdd:cd09940    6 LWFVGEMERDTAENRLENRPDGTYLVR-VRPQGETQYALSIKYNGDVKHMKIEQRsDGLYYLSESRHFKSLVELVNYYER 84

                         90
                 ....*....|....*...
gi 568928613 143 ESLAQYNPKLDVKLTYPV 160
Cdd:cd09940   85 NSLGENFAGLDTTLKWPY 102

Src homology 2 (SH2) domain found in suppressor of cytokine signaling (SOCS) proteins; SH2 domain found in SOCS proteins. SOCS was first recognized as a group of cytokine-inducible SH2 (CIS) domain proteins comprising eight family members in human (CIS and SOCS1-SOCS7). In addition to the SH2 domain, SOCS proteins have a variable N-terminal domain and a conserved SOCS box in the C-terminal domain. SOCS proteins bind to a substrate via their SH2 domain. The prototypical members, CIS and SOCS1-SOCS3, have been shown to regulate growth hormone signaling in vitro and in a classic negative feedback response compete for binding at phosphotyrosine sites in JAK kinase and receptor pathways to displace effector proteins and target bound receptors for proteasomal degradation. Loss of SOCS activity results in excessive cytokine signaling associated with a variety of hematopoietic, autoimmune, and inflammatory diseases and certain cancers. Members (SOCS4-SOCS7) were identified by their conserved SOCS box, an adapter motif of 3 helices that associates substrate binding domains, such as the SOCS SH2 domain, ankryin, and WD40 with ubiquitin ligase components. These show limited cytokine induction. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  65 WYWGDISREEVNDKLRDMPDGTFLVRDASTKMqgdYTLTL--RKGGNNKLIKIYHRDGKYGF---SEPLTFTSVVELINH 139
Cdd:cd10387   12 WYWGPITRWEAEGKLANVPDGSFLVRDSSDDR---YLLSLsfRSHGKTLHTRIEHSNGRFSFyeqPDVEGHTSIVDLIEH 88

Src homology 2 (SH2) domain found in Carboxyl-Terminal Src Kinase (Csk); Both the C-terminal Src kinase (CSK) and CSK-homologous kinase (CHK) are members of the CSK-family of protein tyrosine kinases. These proteins suppress activity of Src-family kinases (SFK) by selectively phosphorylating the conserved C-terminal tail regulatory tyrosine by a similar mechanism. CHK is also capable of inhibiting SFKs by a non-catalytic mechanism that involves binding of CHK to SFKs to form stable protein complexes. The unphosphorylated form of SFKs is inhibited by CSK and CHK by a two-step mechanism. The first step involves the formation of a complex of SFKs with CSK/CHK with the SFKs in the complex are inactive. The second step, involves the phosphorylation of the C-terminal tail tyrosine of SFKs, which then dissociates and adopt an inactive conformation. The structural basis of how the phosphorylated SFKs dissociate from CSK/CHK to adopt the inactive conformation is not known. The inactive conformation of SFKs is stabilized by two intramolecular inhibitory interactions: (a) the pYT:SH2 interaction in which the phosphorylated C-terminal tail tyrosine (YT) binds to the SH2 domain, and (b) the linker:SH3 interaction of which the SH2-kinase domain linker binds to the SH3 domain. SFKs are activated by multiple mechanisms including binding of the ligands to the SH2 and SH3 domains to displace the two inhibitory intramolecular interactions, autophosphorylation, and dephosphorylation of YT. By selective phosphorylation and the non-catalytic inhibitory mechanism CSK and CHK are able to inhibit the active forms of SFKs. CSK and CHK are regulated by phosphorylation and inter-domain interactions. They both contain SH3, SH2, and kinase domains separated by the SH3-SH2 connector and SH2 kinase linker, intervening segments separating the three domains. They lack a conserved tyrosine phosphorylation site in the kinase domain and the C-terminal tail regulatory tyrosine phosphorylation site. The CSK SH2 domain is crucial for stabilizing the kinase domain in the active conformation. A disulfide bond here regulates CSK kinase activity. The subcellular localization and activity of CSK are regulated by its SH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  65 WYWGDISREEVNDKLRDMPDGTFLVRDaSTKMQGDYTLTLRKGGNNKLIKIYHRDGKYGFSEPLTFTSVVELINHYHHES 144
Cdd:cd09937    5 WFHGKISREEAERLLQPPEDGLFLVRE-STNYPGDYTLCVSFEGKVEHYRVIYRNGKLTIDEEEYFENLIQLVEHYTKDA 83

Src homology 2 (SH2) domain found in cytokine-inducible SH2-containing protein (CIS); CIS family members are known to be cytokine-inducible negative regulators of cytokine signaling. The expression of the CIS gene can be induced by IL2, IL3, GM-CSF and EPO in hematopoietic cells. Proteasome-mediated degradation of this protein has been shown to be involved in the inactivation of the erythropoietin receptor. Suppressor of cytokine signalling (SOCS) was first recognized as a group of cytokine-inducible SH2 (CIS) domain proteins comprising eight family members in human (CIS and SOCS1-SOCS7). In addition to the SH2 domain, SOCS proteins have a variable N-terminal domain and a conserved SOCS box in the C-terminal domain. SOCS proteins bind to a substrate via their SH2 domain. The prototypical members, CIS and SOCS1-SOCS3, have been shown to regulate growth hormone signaling in vitro and in a classic negative feedback response compete for binding at phosphotyrosine sites in JAK kinase and receptor pathways to displace effector proteins and target bound receptors for proteasomal degradation. Loss of SOCS activity results in excessive cytokine signaling associated with a variety of hematopoietic, autoimmune, and inflammatory diseases and certain cancers. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  60 LQDAEWYWGDISREEVNDKLRDMPDGTFLVRDAStkmQGDYTLTL----RKGGNNklIKIYHRDGKY-------GFSEPL 128
Cdd:cd10718    1 LRESGWYWGSITASEAHQALQKAPEGTFLVRDSS---HPSYMLTLsvktTRGPTN--VRIEYSDGSFrldssslARPRLL 75

                         90
                 ....*....|..
gi 568928613 129 TFTSVVELINHY 140
Cdd:cd10718   76 SFPDVVSLVQHY 87

SH2 domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 568928613  358 WFVEDINRVQAEDLLY-GKPDGAFLIRES-SKKGCYACSVVRGSE 400
Cdd:pfam00017   1 WYHGKISRQEAERLLLnGKPDGTFLVRESeSTPGGYTLSVRDDGK 45

Src homology 2 (SH2) domain found in suppressor of cytokine signaling (SOCS) proteins; SH2 domain found in SOCS proteins. SOCS was first recognized as a group of cytokine-inducible SH2 (CIS) domain proteins comprising eight family members in human (CIS and SOCS1-SOCS7). In addition to the SH2 domain, SOCS proteins have a variable N-terminal domain and a conserved SOCS box in the C-terminal domain. SOCS proteins bind to a substrate via their SH2 domain. The prototypical members, CIS and SOCS1-SOCS3, have been shown to regulate growth hormone signaling in vitro and in a classic negative feedback response compete for binding at phosphotyrosine sites in JAK kinase and receptor pathways to displace effector proteins and target bound receptors for proteasomal degradation. Loss of SOCS activity results in excessive cytokine signaling associated with a variety of hematopoietic, autoimmune, and inflammatory diseases and certain cancers. Members (SOCS4-SOCS7) were identified by their conserved SOCS box, an adapter motif of 3 helices that associates substrate binding domains, such as the SOCS SH2 domain, ankryin, and WD40 with ubiquitin ligase components. These show limited cytokine induction. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  54 KDSFISLQDAEWYWGDISREEVNDKLRDMPDGTFLVRDASTKMqgdYTLTLRKGGNNKL--IKIYHRDGKYGFSEPLTFT 131
Cdd:cd10388    1 TASLRELKDCGWYWGPMSWEDAEKVLSNKPDGSFLVRDSSDDR---YIFSLSFRSQGSVhhTRIEQYQGTFSLGSRNKFV 77

                         90
                 ....*....|
gi 568928613 132 ----SVVELI 137
Cdd:cd10388   78 drsqSLVEFI 87

Src homology 2 (SH2) domain found in B-cell linker (BLNK) protein and SH2 domain-containing leukocyte protein of 76 kDa (SLP-76); BLNK (also known as SLP-65 or BASH) is an important adaptor protein expressed in B-lineage cells. BLNK consists of a N-terminal sterile alpha motif (SAM) domain and a C-terminal SH2 domain. BLNK is a cytoplasmic protein, but a part of it is bound to the plasma membrane through an N-terminal leucine zipper motif and transiently bound to a cytoplasmic domain of Iga through its C-terminal SH2 domain upon B cell antigen receptor (BCR)-stimulation. A non-ITAM phosphotyrosine in Iga is necessary for the binding with the BLNK SH2 domain and/or for normal BLNK function in signaling and B cell activation. Upon phosphorylation BLNK binds Btk and PLCgamma2 through their SH2 domains and mediates PLCgamma2 activation by Btk. BLNK also binds other signaling molecules such as Vav, Grb2, Syk, and HPK1. BLNK has been shown to be necessary for BCR-mediated Ca2+ mobilization, for the activation of mitogen-activated protein kinases such as ERK, JNK, and p38 in a chicken B cell line DT40, and for activation of transcription factors such as NF-AT and NF-kappaB in human or mouse B cells. BLNK is involved in B cell development, B cell survival, activation, proliferation, and T-independent immune responses. BLNK is structurally homologous to SLP-76. SLP-76 and (linker for activation of T cells) LAT are adaptor/linker proteins in T cell antigen receptor activation and T cell development. BLNK interacts with many downstream signaling proteins that interact directly with both SLP-76 and LAT. New data suggest functional complementation of SLP-76 and LAT in T cell antigen receptor function with BLNK in BCR function. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  59 SLQDAEWYWGDISREEVNDKLRDM-PDGTFLVRDASTKM-QGDYTLTLRKggNNKL--IKIYHRDGKYGFS--------E 126
Cdd:cd09929    7 DLLPKEWYAGNIDRKEAEEALRRSnKDGTFLVRDSSGKDsSQPYTLMVLY--NDKVynIQIRFLENTRQYAlgtglrgeE 84

                         90       100       110
                 ....*....|....*....|....*....|....*...
gi 568928613 127 plTFTSVVELINHYHHESL----AQYNPKLDVKLTYPV 160
Cdd:cd09929   85 --TFSSVAEIIEHHQKTPLllidGKDNTKDSTCLLYAA 120

Src homology 2 (SH2) domain found in suppressor of cytokine signaling (SOCS) proteins; SH2 domain found in SOCS proteins. SOCS was first recognized as a group of cytokine-inducible SH2 (CIS) domain proteins comprising eight family members in human (CIS and SOCS1-SOCS7). In addition to the SH2 domain, SOCS proteins have a variable N-terminal domain and a conserved SOCS box in the C-terminal domain. SOCS proteins bind to a substrate via their SH2 domain. The prototypical members, CIS and SOCS1-SOCS3, have been shown to regulate growth hormone signaling in vitro and in a classic negative feedback response compete for binding at phosphotyrosine sites in JAK kinase and receptor pathways to displace effector proteins and target bound receptors for proteasomal degradation. Loss of SOCS activity results in excessive cytokine signaling associated with a variety of hematopoietic, autoimmune, and inflammatory diseases and certain cancers. Members (SOCS4-SOCS7) were identified by their conserved SOCS box, an adapter motif of 3 helices that associates substrate binding domains, such as the SOCS SH2 domain, ankryin, and WD40 with ubiquitin ligase components. These show limited cytokine induction. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  54 KDSFISLQDAEWYWGDISREEVNDKLRDMPDGTFLVRDAStkmQGD--YTLTLRKGGNNKLIKIYHRDGKYGFSE-PLTF 130
Cdd:cd10382    1 TRTSAMLDASGFYWGPLSVEEAHAKLKREPVGTFLIRDSR---QKNcfFALSVKMASGPVSIRILFKAGKFSLDGsKESF 77

                         90
                 ....*....|
gi 568928613 131 TSVVELINHY 140
Cdd:cd10382   78 DCLFKLLEHY 87

N-terminal Src homology 2 (N-SH2) domain in Phospholipase C gamma; Phospholipase C gamma is a signaling molecule that is recruited to the C-terminal tail of the receptor upon autophosphorylation of a highly conserved tyrosine. PLCgamma is composed of a Pleckstrin homology (PH) domain followed by an elongation factor (EF) domain, 2 catalytic regions of PLC domains that flank 2 tandem SH2 domains (N-SH2, C-SH2), and ending with a SH3 domain and C2 domain. N-SH2 SH2 domain-mediated interactions represent a crucial step in transmembrane signaling by receptor tyrosine kinases. SH2 domains recognize phosphotyrosine (pY) in the context of particular sequence motifs in receptor phosphorylation sites. Both N-SH2 and C-SH2 have a very similar binding affinity to pY. But in growth factor stimulated cells these domains bind to different target proteins. N-SH2 binds to pY containing sites in the C-terminal tails of tyrosine kinases and other receptors. Recently it has been shown that this interaction is mediated by phosphorylation-independent interactions between a secondary binding site found exclusively on the N-SH2 domain and a region of the FGFR1 tyrosine kinase domain. This secondary site on the SH2 cooperates with the canonical pY site to regulate selectivity in mediating a specific cellular process. C-SH2 binds to an intramolecular site on PLCgamma itself which allows it to hydrolyze phosphatidylinositol-4,5-bisphosphate into diacylglycerol and inositol triphosphate. These then activate protein kinase C and release calcium. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  64 EWYWGDIS--REEVNDKLRDM---PDGTFLVRDaSTKMQGDYTLTLRKGGNNKLIKIYHRDG----KYGFSEPLTFTSVV 134
Cdd:cd10341    5 PWFHGKLGdgRDEAEKLLLEYcegGDGTFLVRE-SETFVGDYTLSFWRNGKVQHCRIRSRQEngekKYYLTDNLVFDSLY 83

                         90
                 ....*....|.
gi 568928613 135 ELINHYHHESL 145
Cdd:cd10341   84 ELIDYYRQNPL 94

Src homology 2 (SH2) domain found in the Vav2 proteins; Proto-oncogene vav is a member of the Dbl family of guanine nucleotide exchange factors (GEF) for the Rho family of GTP binding proteins. All vavs are activated by tyrosine phosphorylation leading to their activation. There are three Vav mammalian family members: Vav1 which is expressed in the hematopoietic system, and Vav2 and Vav3 are more ubiquitously expressed. Vav2 is a GEF for RhoA, RhoB and RhoG and may activate Rac1 and Cdc42. Vav2 has been shown to interact with CD19 and Grb2. Alternatively spliced transcript variants encoding different isoforms have been found for Vav2. Vav proteins are involved in several processes that require cytoskeletal reorganization, such as the formation of the immunological synapse (IS), phagocytosis, platelet aggregation, spreading, and transformation. Vavs function as guanine nucleotide exchange factors (GEFs) for the Rho/Rac family of GTPases. Vav family members have several conserved motifs/domains including: a leucine-rich region, a leucine-zipper, a calponin homology (CH) domain, an acidic domain, a Dbl-homology (DH) domain, a pleckstrin homology (PH) domain, a cysteine-rich domain, 2 SH3 domains, a proline-rich region, and a SH2 domain. Vavs are the only known Rho GEFs that have both the DH/PH motifs and SH2/SH3 domains in the same protein. The leucine-rich helix-loop-helix (HLH) domain is thought to be involved in protein heterodimerization with other HLH proteins and it may function as a negative regulator by forming inactive heterodimers. The CH domain is usually involved in the association with filamentous actin, but in Vav it controls NFAT stimulation, Ca2+ mobilization, and its transforming activity. Acidic domains are involved in protein-protein interactions and contain regulatory tyrosines. The DH domain is a GDP-GTP exchange factor on Rho/Rac GTPases. The PH domain in involved in interactions with GTP-binding proteins, lipids and/or phosphorylated serine/threonine residues. The SH3 domain is involved in localization of proteins to specific sites within the cell interacting with protein with proline-rich sequences. The SH2 domain mediates a high affinity interaction with tyrosine phosphorylated proteins. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  65 WYWGDISREEVNDKLRDMPDGTFLVRDASTKMQgDYTLTLRKGGNNKLIKIYHRDGKYGFSEPLTFTSVVELINHYHHES 144
Cdd:cd10406    7 WFAGNMERQQTDNLLKSHASGTYLIRERPAEAE-RFAISIKFNDEVKHIKVVEKDNWIHITEAKKFESLLELVEYYQCHS 85

                         90
                 ....*....|....*..
gi 568928613 145 LAQYNPKLDVKLTYPVS 161
Cdd:cd10406   86 LKESFKQLDTTLKYPYK 102

Src homology 2 domain found in cancer-related signaling adaptor protein CRK; SH2 domain in the CRK proteins. CRKI (SH2-SH3) and CRKII (SH2-SH3-SH3) are splicing isoforms of the oncoprotein CRK. CRKs regulate transcription and cytoskeletal reorganization for cell growth and motility by linking tyrosine kinases to small G proteins. The SH2 domain of CRK associates with tyrosine-phosphorylated receptors or components of focal adhesions, such as p130Cas and paxillin. CRK transmits signals to small G proteins through effectors that bind its SH3 domain, such as C3G, the guanine-nucleotide exchange factor (GEF) for Rap1 and R-Ras, and DOCK180, the GEF for Rac6. The binding of p130Cas to the CRK-C3G complex activates Rap1, leading to regulation of cell adhesion, and activates R-Ras, leading to JNK-mediated activation of cell proliferation, whereas the binding of CRK DOCK180 induces Rac1-mediated activation of cellular migration. The activity of the different splicing isoforms varies greatly with CRKI displaying substantial transforming activity, CRKII less so, and phosphorylated CRKII with no biological activity whatsoever. CRKII has a linker region with a phosphorylated Tyr and an additional C-terminal SH3 domain. The phosphorylated Tyr creates a binding site for its SH2 domain which disrupts the association between CRK and its SH2 target proteins. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 568928613  57 FISLQDAEWYWGDISREEVNDKLRDMPDGTFLVRDASTkMQGDYTLTLR 105
Cdd:cd09926    1 FDSSDRSSWYFGPMSRQEAQELLQGQRHGVFLVRDSST-IPGDYVLSVS 48

Src homology 2 (SH2) domain found in Nck; Nck proteins are adaptors that modulate actin cytoskeleton dynamics by linking proline-rich effector molecules to tyrosine kinases or phosphorylated signaling intermediates. There are two members known in this family: Nck1 (Nckalpha) and Nck2 (Nckbeta and Growth factor receptor-bound protein 4 (Grb4)). They are characterized by having 3 SH3 domains and a C-terminal SH2 domain. Nck1 and Nck2 have overlapping functions as determined by gene knockouts. Both bind receptor tyrosine kinases and other tyrosine-phosphorylated proteins through their SH2 domains. In addition they also bind distinct targets. Neuronal signaling proteins: EphrinB1, EphrinB2, and Disabled-1 (Dab-1) all bind to Nck-2 exclusively. And in the case of PDGFR, Tyr(P)751 binds to Nck1 while Tyr(P)1009 binds to Nck2. Nck1 and Nck2 have a role in the infection process of enteropathogenic Escherichia coli (EPEC). Their SH3 domains are involved in recruiting and activating the N-WASP/Arp2/3 complex inducing actin polymerization resulting in the production of pedestals, dynamic bacteria-presenting protrusions of the plasma membrane. A similar thing occurs in the vaccinia virus where motile plasma membrane projections are formed beneath the virus. Recently it has been shown that the SH2 domains of both Nck1 and Nck2 bind the G-protein coupled receptor kinase-interacting protein 1 (GIT1) in a phosphorylation-dependent manner. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 568928613  64 EWYWGDISREEVNDKLRDMP-DGTFLVRDASTKmQGDYTLTLRKGGNNKLIKIYHRDGKYGFSEPlTFTSVVELINHY 140
Cdd:cd10409    2 EWYYGNVTRHQAECALNERGvEGDFLIRDSESS-PSDFSVSLKAVGKNKHFKVQLVDNVYCIGQR-RFNSMDELVEHY 77

Src homology 2 (SH2) domain found in the Vav1 proteins; Proto-oncogene vav is a member of the Dbl family of guanine nucleotide exchange factors (GEF) for the Rho family of GTP binding proteins. All vavs are activated by tyrosine phosphorylation leading to their activation. There are three Vav mammalian family members: Vav1 which is expressed in the hematopoietic system, and Vav2 and Vav3 are more ubiquitously expressed. Vav1 plays a role in T-cell and B-cell development and activation. It has been identified as the specific binding partner of Nef proteins from HIV-1, resulting in morphological changes, cytoskeletal rearrangements, and the JNK/SAPK signaling cascade, leading to increased levels of viral transcription and replication. Vav1 has been shown to interact with Ku70, PLCG1, Lymphocyte cytosolic protein 2, Janus kinase 2, SIAH2, S100B, Abl gene, ARHGDIB, SHB, PIK3R1, PRKCQ, Grb2, MAPK1, Syk, Linker of activated T cells, Cbl gene and EZH2. Vav proteins are involved in several processes that require cytoskeletal reorganization, such as the formation of the immunological synapse (IS), phagocytosis, platelet aggregation, spreading, and transformation. Vavs function as guanine nucleotide exchange factors (GEFs) for the Rho/Rac family of GTPases. Vav family members have several conserved motifs/domains including: a leucine-rich region, a leucine-zipper, a calponin homology (CH) domain, an acidic domain, a Dbl-homology (DH) domain, a pleckstrin homology (PH) domain, a cysteine-rich domain, 2 SH3 domains, a proline-rich region, and a SH2 domain. Vavs are the only known Rho GEFs that have both the DH/PH motifs and SH2/SH3 domains in the same protein. The leucine-rich helix-loop-helix (HLH) domain is thought to be involved in protein heterodimerization with other HLH proteins and it may function as a negative regulator by forming inactive heterodimers. The CH domain is usually involved in the association with filamentous actin, but in Vav it controls NFAT stimulation, Ca2+ mobilization, and its transforming activity. Acidic domains are involved in protein-protein interactions and contain regulatory tyrosines. The DH domain is a GDP-GTP exchange factor on Rho/Rac GTPases. The PH domain in involved in interactions with GTP-binding proteins, lipids and/or phosphorylated serine/threonine residues. The SH3 domain is involved in localization of proteins to specific sites within the cell interacting with protein with proline-rich sequences. The SH2 domain mediates a high affinity interaction with tyrosine phosphorylated proteins. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  65 WYWGDISREEVNDKLRDMPDGTFLVRDaSTKMQGDYTLTLRKGGNNKLIKIYHRDGKYGFSEPLTFTSVVELINHYHHES 144
Cdd:cd10405    7 WYAGPMERAGAESILANRSDGTYLVRQ-RVKDAAEFAISIKYNVEVKHIKIMTAEGLYRITEKKAFRGLTELVEFYQQNS 85

                         90
                 ....*....|....*
gi 568928613 145 LAQYNPKLDVKLTYP 159
Cdd:cd10405   86 LKDCFKSLDTTLQFP 100

Src homology 2 (SH2) domain found in Lyn; Lyn is a member of the Src non-receptor type tyrosine kinase family of proteins and is expressed in the hematopoietic cells, in neural tissues, liver, and adipose tissue. There are two alternatively spliced forms of Lyn. Lyn plays an inhibitory role in myeloid lineage proliferation. Following engagement of the B cell receptors, Lyn undergoes rapid phosphorylation and activation, triggering a cascade of signaling events mediated by Lyn phosphorylation of tyrosine residues within the immunoreceptor tyrosine-based activation motifs (ITAM) of the receptor proteins, and subsequent recruitment and activation of other kinases including Syk, phospholipase C2 (PLC2) and phosphatidyl inositol-3 kinase. These kinases play critical roles in proliferation, Ca2+ mobilization and cell differentiation. Lyn plays an essential role in the transmission of inhibitory signals through phosphorylation of tyrosine residues within the immunoreceptor tyrosine-based inhibitory motifs (ITIM) in regulatory proteins such as CD22, PIR-B and FC RIIb1. Their ITIM phosphorylation subsequently leads to recruitment and activation of phosphatases such as SHIP-1 and SHP-1 which further down modulate signaling pathways, attenuate cell activation and can mediate tolerance. Lyn also plays a role in the insulin signaling pathway. Activated Lyn phosphorylates insulin receptor substrate 1 (IRS1) leading to an increase in translocation of Glut-4 to the cell membrane and increased glucose utilization. It is the primary Src family member involved in signaling downstream of the B cell receptor. Lyn plays an unusual, 2-fold role in B cell receptor signaling; it is essential for initiation of signaling but is also later involved in negative regulation of the signal. Lyn has a unique N-terminal domain, an SH3 domain, an SH2 domain, a kinase domain and a regulatory tail, as do the other members of the family. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  64 EWYWGDISREEVNDKLRDMPD--GTFLVRDASTkMQGDYTLTLR----KGGNN-KLIKIYHRD-GKYGFSEPLTFTSVVE 135
Cdd:cd10364    4 EWFFKDITRKDAERQLLAPGNsaGAFLIRESET-LKGSYSLSVRdydpQHGDViKHYKIRSLDnGGYYISPRITFPCISD 82

                 ....*....
gi 568928613 136 LINHYHHES 144
Cdd:cd10364   83 MIKHYQKQS 91

C-terminal Src homology 2 (C-SH2) domain found in SH2 domain Phosphatases (SHP) proteins; The SH2 domain phosphatases (SHP-1, SHP-2/Syp, Drosophila corkscrew (csw), and Caenorhabditis elegans Protein Tyrosine Phosphatase (Ptp-2)) are cytoplasmic signaling enzymes. They are both targeted and regulated by interactions of their SH2 domains with phosphotyrosine docking sites. These proteins contain two SH2 domains (N-SH2, C-SH2) followed by a tyrosine phosphatase (PTP) domain, and a C-terminal extension. Shp1 and Shp2 have two tyrosyl phosphorylation sites in their C-tails, which are phosphorylated differentially by receptor and nonreceptor PTKs. Csw retains the proximal tyrosine and Ptp-2 lacks both sites. Shp-binding proteins include receptors, scaffolding adapters, and inhibitory receptors. Some of these bind both Shp1 and Shp2 while others bind only one. Most proteins that bind a Shp SH2 domain contain one or more immuno-receptor tyrosine-based inhibitory motifs (ITIMs): [SIVL]xpYxx[IVL]. Shp1 N-SH2 domain blocks the catalytic domain and keeps the enzyme in the inactive conformation, and is thus believed to regulate the phosphatase activity of SHP-1. Its C-SH2 domain is thought to be involved in searching for phosphotyrosine activators. The SHP2 N-SH2 domain is a conformational switch; it either binds and inhibits the phosphatase, or it binds phosphoproteins and activates the enzyme. The C-SH2 domain contributes binding energy and specificity, but it does not have a direct role in activation. Csw SH2 domain function is essential, but either SH2 domain can fulfill this requirement. The role of the csw SH2 domains during Sevenless receptor tyrosine kinase (SEV) signaling is to bind Daughter of Sevenless rather than activated SEV. Ptp-2 acts in oocytes downstream of sheath/oocyte gap junctions to promote major sperm protein (MSP)-induced MAP Kinase (MPK-1) phosphorylation. Ptp-2 functions in the oocyte cytoplasm, not at the cell surface to inhibit multiple RasGAPs, resulting in sustained Ras activation. It is thought that MSP triggers PTP-2/Ras activation and ROS production to stimulate MPK-1 activity essential for oocyte maturation and that secreted MSP domains and Cu/Zn superoxide dismutases function antagonistically to control ROS and MAPK signaling. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 568928613  65 WYWGDISREEVNDKLRDMP-DGTFLVRDASTKmQGDYTLTLRKGgNNKL--IKIYHRDGKYGFSEPLTFTSVVELINHY 140
Cdd:cd09931    2 WFHGHLSGKEAEKLLLEKGkPGSFLVRESQSK-PGDFVLSVRTD-DDKVthIMIRCQGGKYDVGGGEEFDSLTDLVEHY 78

Src homology 2 (SH2) domain found in suppressor of cytokine signaling (SOCS) proteins; SH2 domain found in SOCS proteins. SOCS was first recognized as a group of cytokine-inducible SH2 (CIS) domain proteins comprising eight family members in human (CIS and SOCS1-SOCS7). In addition to the SH2 domain, SOCS proteins have a variable N-terminal domain and a conserved SOCS box in the C-terminal domain. SOCS proteins bind to a substrate via their SH2 domain. The prototypical members, CIS and SOCS1-SOCS3, have been shown to regulate growth hormone signaling in vitro and in a classic negative feedback response compete for binding at phosphotyrosine sites in JAK kinase and receptor pathways to displace effector proteins and target bound receptors for proteasomal degradation. Loss of SOCS activity results in excessive cytokine signaling associated with a variety of hematopoietic, autoimmune, and inflammatory diseases and certain cancers. Members (SOCS4-SOCS7) were identified by their conserved SOCS box, an adapter motif of 3 helices that associates substrate binding domains, such as the SOCS SH2 domain, ankryin, and WD40 with ubiquitin ligase components. These show limited cytokine induction. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  60 LQDAEWYWGDISREEVNDKLRDMPDGTFLVRDASTKMQGdYTLTLRKGGNNKLIKIyHRDGKYGFSE--------PLTFT 131
Cdd:cd10384    7 LQESGFYWSTVSGKEANLLLSAEPAGTFLIRDSSDQRHF-FTLSVKTESGTKNLRI-QCEGGSFSLQtdprstqpVPRFD 84

                 ....*....
gi 568928613 132 SVVELINHY 140
Cdd:cd10384   85 CVLKLVHHY 93

C-terminal Src homology 2 (SH2) domain found in Ras GTPase-activating protein 1 (GAP); RasGAP is part of the GAP1 family of GTPase-activating proteins. The protein is located in the cytoplasm and stimulates the GTPase activity of normal RAS p21, but not its oncogenic counterpart. Acting as a suppressor of RAS function, the protein enhances the weak intrinsic GTPase activity of RAS proteins resulting in RAS inactivation, thereby allowing control of cellular proliferation and differentiation. Mutations leading to changes in the binding sites of either protein are associated with basal cell carcinomas. Alternative splicing results in two isoforms. The shorter isoform which lacks the N-terminal hydrophobic region, has the same activity, and is expressed in placental tissues. In general longer isoform contains 2 SH2 domains, a SH3 domain, a pleckstrin homology (PH) domain, and a calcium-dependent phospholipid-binding C2 domain. The C-terminus contains the catalytic domain of RasGap which catalyzes the activation of Ras by hydrolyzing GTP-bound active Ras into an inactive GDP-bound form of Ras. This model contains the C-terminal SH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 568928613  64 EWYWGDISREEVNDKL-RDMPDGTFLVRDaSTKMQGDYTLTLRKGGNNKLIKIYHRDGKYGFSEPLTFTSVVELINHY 140
Cdd:cd10354    1 IWFHGKISREEAYNMLvKVGGPGSFLVRE-SDNTPGDYSLSFRVNEGIKHFKIIPTGNNQFMMGGRYFSSLDDVIDRY 77

Src homology 2 domain found in SH2 domain-containing adapter proteins B, D, E, and F (SHB, SHD, SHE, SHF); SHB, SHD, SHE, and SHF are SH2 domain-containing proteins that play various roles throughout the cell. SHB functions in generating signaling compounds in response to tyrosine kinase activation. SHB contains proline-rich motifs, a phosphotyrosine binding (PTB) domain, tyrosine phosphorylation sites, and a SH2 domain. SHB mediates certain aspects of platelet-derived growth factor (PDGF) receptor-, fibroblast growth factor (FGF) receptor-, neural growth factor (NGF) receptor TRKA-, T cell receptor-, interleukin-2 (IL-2) receptor- and focal adhesion kinase- (FAK) signaling. SRC-like FYN-Related Kinase FRK/RAK (also named BSK/IYK or GTK) and SHB regulate apoptosis, proliferation and differentiation. SHB promotes apoptosis and is also required for proper mitogenicity, spreading and tubular morphogenesis in endothelial cells. SHB also plays a role in preventing early cavitation of embryoid bodies and reduces differentiation to cells expressing albumin, amylase, insulin and glucagon. SHB is a multifunctional protein that has difference responses in different cells under various conditions. SHE is expressed in heart, lung, brain, and skeletal muscle, while expression of SHD is restricted to the brain. SHF is mainly expressed in skeletal muscle, brain, liver, prostate, testis, ovary, small intestine, and colon. SHD may be a physiological substrate of c-Abl and may function as an adapter protein in the central nervous system. It is also thought to be involved in apoptotic regulation. SHD contains five YXXP motifs, a substrate sequence preferred by Abl tyrosine kinases, in addition to a poly-proline rich region and a C-terminal SH2 domain. SHE contains two pTry protein binding domains, protein interaction domain (PID) and a SH2 domain, followed by a glycine-proline rich region, all of which are N-terminal to the phosphotyrosine binding (PTB) domain. SHF contains four putative tyrosine phosphorylation sites and an SH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  65 WYWGDISREEVNDKLRDMPDGTFLVRDASTKMQgDYTLTLRKGGNNKLIKIYH-RDGKY---GFSEPltFTSVVELINHY 140
Cdd:cd09945    3 WYHGAITRIEAESLLRPCKEGSYLVRNSESTKQ-DYSLSLKSAKGFMHMRIQRnETGQYilgQFSRP--FETIPEMIRHY 79

Src homology 2 (SH2) domain found in SH2 domain-bearing protein kinases A and C (ShkA and ShkC); SH2-bearing genes cloned from Dictyostelium include two transcription factors, STATa and STATc, and a signaling factor, SHK1 (shkA). A database search of the Dictyostelium discoideum genome revealed two additional putative STAT sequences, dd-STATb and dd-STATd, and four additional putative SHK genes, dd-SHK2 (shkB), dd-SHK3 (shkC), dd-SHK4 (shkD), and dd-SHK5 (shkE). This model contains members of shkA and shkC. All of the SHK members are most closely related to the protein kinases found in plants. However these kinases in plants are not conjugated to any SH2 or SH2-like sequences. Alignment data indicates that the SHK SH2 domains carry some features of the STAT SH2 domains in Dictyostelium. When STATc's linker domain was used for a BLAST search, the sequence between the protein kinase domain and the SH2 domain (the linker) of SHK was recovered, suggesting a close relationship among these molecules within this region. SHK's linker domain is predicted to contain an alpha-helix which is indeed homologous to that of STAT. Based on the phylogenetic alignment, SH2 domains can be grouped into two categories, STAT-type and Src-type. SHK family members are in between, but are closer to the STAT-type which indicates a close relationship between SHK and STAT families in their SH2 domains and further supports the notion that SHKs linker-SH2 domain evolved from STAT or STATL (STAT-like Linker-SH2) domain found in plants. In SHK, STAT, and SPT6, the linker-SH2 domains all reside exclusively in the C-terminal regions. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

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                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 568928613  55 DSFISLQDAEWYWGDISREEVNDKLRDMPDGTFLVRDASTKmQGDYTLT-LRKGGNNKLIKIYHRDGKYGFSEPLtFTSV 133
Cdd:cd10356    2 DKIRELMECAWFHGDISTSESENRLNGKPEGTFLVRFSTSE-PGAYTISkVSKNGGISHQRIHRPGGKFQVNNSK-YLSV 79

                 ....
gi 568928613 134 VELI 137
Cdd:cd10356   80 KELI 83