Amyloid beta (A4) Precursor protein-Binding, family B, member 1 Interacting Protein pleckstrin homology (PH) domain; APBB1IP consists of a Ras-associated (RA) domain, a PH domain, a family-specific BPS region, and a C-terminal SH2 domain. Grb7, Grb10 and Grb14 are paralogs that are also present in this hierarchy. These adapter proteins bind a variety of receptor tyrosine kinases, including the insulin and insulin-like growth factor-1 (IGF1) receptors. Grb10 and Grb14 are important tissue-specific negative regulators of insulin and IGF1 signaling based and may contribute to type 2 (non-insulin-dependent) diabetes in humans. RA-PH function as a single structural unit and is dimerized via a helical extension of the PH domain. The PH domain here are proposed to bind phosphoinositides non-cannonically ahd are unlikely to bind an activated GTPase. The tandem RA-PH domains are present in a second adapter-protein family, MRL proteins, Caenorhabditis elegans protein MIG-1012, the mammalian proteins RIAM and lamellipodin and the Drosophila melanogaster protein Pico12, all of which are Ena/VASP-binding proteins involved in actin-cytoskeleton rearrangement. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697 125 SSNTYPEIHGFLHAKEQGKKSWKKAYFFLRRSGLYFSTKGTSKEPRHLQFFSEFSTSNVYMSLAGKKKHGAPTPYGFCFK 204
Cdd:cd01259     1 NSVSCPEIEGFLYLKEDGKKSWKKRYFVLRASGLYYSPKGKSKESRDLQCLAQFDDYNVYTGLNGKKKYKAPTDFGFCLK 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....
gi 1958763697 205 PTKAG--GPRDLKMLCAEEDQSRMCWVTAIRLLKYGMQLYQNYM 246
Cdd:cd01259    81 PNKQQekGSKDIKYLCAEDEQSRTCWLTAIRLAKYGKQLYENYR 124

BPS (Between PH and SH2); The BPS (Between PH and SH2) domain, comprised of 2 beta strands and a C-terminal helix, is an approximately 45 residue region found in the adaptor proteins Grb7/10/14 that mediates inhibition of the tyrosine kinase domain of the insulin receptor by binding of the N-terminal portion of the BPS domain to the substrate peptide groove of the kinase, acting as a pseudosubstrate inhibitor.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1958763697 264 RSVSENSLVAMDFSGQKTRVIDNPTEALSVAVEEGLAWRKKGCLRL 309
Cdd:pfam08947   1 RSVSESSLVAMDFSGAGGRVIENPEEALSEAEEEGAAWRKKTLRRC 46

Amyloid beta (A4) Precursor protein-Binding, family B, member 1 Interacting Protein pleckstrin homology (PH) domain; APBB1IP consists of a Ras-associated (RA) domain, a PH domain, a family-specific BPS region, and a C-terminal SH2 domain. Grb7, Grb10 and Grb14 are paralogs that are also present in this hierarchy. These adapter proteins bind a variety of receptor tyrosine kinases, including the insulin and insulin-like growth factor-1 (IGF1) receptors. Grb10 and Grb14 are important tissue-specific negative regulators of insulin and IGF1 signaling based and may contribute to type 2 (non-insulin-dependent) diabetes in humans. RA-PH function as a single structural unit and is dimerized via a helical extension of the PH domain. The PH domain here are proposed to bind phosphoinositides non-cannonically ahd are unlikely to bind an activated GTPase. The tandem RA-PH domains are present in a second adapter-protein family, MRL proteins, Caenorhabditis elegans protein MIG-1012, the mammalian proteins RIAM and lamellipodin and the Drosophila melanogaster protein Pico12, all of which are Ena/VASP-binding proteins involved in actin-cytoskeleton rearrangement. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697 125 SSNTYPEIHGFLHAKEQGKKSWKKAYFFLRRSGLYFSTKGTSKEPRHLQFFSEFSTSNVYMSLAGKKKHGAPTPYGFCFK 204
Cdd:cd01259     1 NSVSCPEIEGFLYLKEDGKKSWKKRYFVLRASGLYYSPKGKSKESRDLQCLAQFDDYNVYTGLNGKKKYKAPTDFGFCLK 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....
gi 1958763697 205 PTKAG--GPRDLKMLCAEEDQSRMCWVTAIRLLKYGMQLYQNYM 246
Cdd:cd01259    81 PNKQQekGSKDIKYLCAEDEQSRTCWLTAIRLAKYGKQLYENYR 124

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 1958763697  332 QPWFHHRISRDEAQQLITRQGpvDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVEDDGEVFhtldDGHTKFTDLIQL 411
Cdd:smart00252   1 QPWYHGFISREEAEKLLKNEG--DGDFLVRDSESSPGDYVLSVRVKGKVKHYRIRRNEDGKFYL----EGGRKFPSLVEL 74

                           90
                   ....*....|
gi 1958763697  412 VEFYQLNKGV 421
Cdd:smart00252  75 VEHYQKNSLG 84

SH2 domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697 334 WFHHRISRDEAQQLItRQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVEDDGevfHTLDDGHtKFTDLIQLVE 413
Cdd:pfam00017   1 WYHGKISRQEAERLL-LNGKPDGTFLVRESESTPGGYTLSVRDDGKVKHYKIQSTDNGG---YYISGGV-KFSSLAELVE 75

                  ..
gi 1958763697 414 FY 415
Cdd:pfam00017  76 HY 77

Ras association (RalGDS/AF-6) domain; RasGTP effectors (in cases of AF6, canoe and RalGDS); putative RasGTP effectors in other cases. Kalhammer et al. have shown that not all RA domains bind RasGTP. Predicted structure similar to that determined, and that of the RasGTP-binding domain of Raf kinase. Predicted RA domains in PLC210 and nore1 found to bind RasGTP. Included outliers (Grb7, Grb14, adenylyl cyclases etc.)

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697    2 TQVIKVYSED---ESSRALEVPSDVTARDVCQLLILKNHYVDD-NSWTLFEHLSHtGVERTVEDHELLTEVLSHWVMEED 77
Cdd:smart00314   2 TFVLRVYVDDlpgGTYKTLRVSSRTTARDVIQQLLEKFHLTDDpEEYVLVEVLPD-GKERVLPDDENPLQLQKLWPRRGP 80

                           90
                   ....*....|
gi 1958763697   78 N-KLYLRKNY 86
Cdd:smart00314  81 NlRFVLRKRD 90

Pleckstrin homology domain; Domain commonly found in eukaryotic signalling proteins. The domain family possesses multiple functions including the abilities to bind inositol phosphates, and various proteins. PH domains have been found to possess inserted domains (such as in PLC gamma, syntrophins) and to be inserted within other domains. Mutations in Brutons tyrosine kinase (Btk) within its PH domain cause X-linked agammaglobulinaemia (XLA) in patients. Point mutations cluster into the positively charged end of the molecule around the predicted binding site for phosphatidylinositol lipids.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697  130 PEIHGFLHAKEQ-GKKSWKKAYFFLRRSGLYFSTKGTSKEPRHLQFFSEFSTSNVYMSLAGKKKhgaptPYGFCFKPTka 208
Cdd:smart00233   1 VIKEGWLYKKSGgGKKSWKKRYFVLFNSTLLYYKSKKDKKSYKPKGSIDLSGCTVREAPDPDSS-----KKPHCFEIK-- 73

                           90       100
                   ....*....|....*....|....*....
gi 1958763697  209 GGPRDLKMLCAEEDQSRMCWVTAIRLLKY 237
Cdd:smart00233  74 TSDRKTLLLQAESEEEREKWVEALRKAIA 102

Amyloid beta (A4) Precursor protein-Binding, family B, member 1 Interacting Protein pleckstrin homology (PH) domain; APBB1IP consists of a Ras-associated (RA) domain, a PH domain, a family-specific BPS region, and a C-terminal SH2 domain. Grb7, Grb10 and Grb14 are paralogs that are also present in this hierarchy. These adapter proteins bind a variety of receptor tyrosine kinases, including the insulin and insulin-like growth factor-1 (IGF1) receptors. Grb10 and Grb14 are important tissue-specific negative regulators of insulin and IGF1 signaling based and may contribute to type 2 (non-insulin-dependent) diabetes in humans. RA-PH function as a single structural unit and is dimerized via a helical extension of the PH domain. The PH domain here are proposed to bind phosphoinositides non-cannonically ahd are unlikely to bind an activated GTPase. The tandem RA-PH domains are present in a second adapter-protein family, MRL proteins, Caenorhabditis elegans protein MIG-1012, the mammalian proteins RIAM and lamellipodin and the Drosophila melanogaster protein Pico12, all of which are Ena/VASP-binding proteins involved in actin-cytoskeleton rearrangement. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697 125 SSNTYPEIHGFLHAKEQGKKSWKKAYFFLRRSGLYFSTKGTSKEPRHLQFFSEFSTSNVYMSLAGKKKHGAPTPYGFCFK 204
Cdd:cd01259     1 NSVSCPEIEGFLYLKEDGKKSWKKRYFVLRASGLYYSPKGKSKESRDLQCLAQFDDYNVYTGLNGKKKYKAPTDFGFCLK 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....
gi 1958763697 205 PTKAG--GPRDLKMLCAEEDQSRMCWVTAIRLLKYGMQLYQNYM 246
Cdd:cd01259    81 PNKQQekGSKDIKYLCAEDEQSRTCWLTAIRLAKYGKQLYENYR 124

Src homology 2 (SH2) domain found in the growth factor receptor bound, subclass 7 (Grb7) proteins; The Grb family binds to the epidermal growth factor receptor (EGFR, erbB1) via their SH2 domains. Grb7 is part of the Grb7 family of proteins which also includes Grb10, and Grb14. They are composed of an N-terminal Proline-rich domain, a Ras Associating-like (RA) domain, a Pleckstrin Homology (PH) domain, a phosphotyrosine interaction region (PIR, BPS) and a C-terminal SH2 domain. The SH2 domains of Grb7, Grb10 and Grb14 preferentially bind to a different RTK. Grb7 binds strongly to the erbB2 receptor, unlike Grb10 and Grb14 which bind weakly to it. Grb7 family proteins are phosphorylated on serine/threonine as well as tyrosine residues. 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 1958763697 328 LHRSQPWFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVEDDGEVFHTLDDGHTKFTD 407
Cdd:cd10413     1 IHRTQPWFHGRISREESQRLIGQQGLVDGVFLVRESQRNPQGFVLSLCHLQKVKHYLILPSEEEGRLYFSMDDGQTRFTD 80

                          90       100
                  ....*....|....*....|....*...
gi 1958763697 408 LIQLVEFYQLNKGVLPCKLKHYCARMAV 435
Cdd:cd10413    81 LLQLVEFHQLNRGILPCLLRHCCTRVAL 108

Ras-associating (RA) domain found in growth factor receptor-bound (Grb) protein 14; Grb14, a member of cytoplasmic adaptor proteins, is a tissue-specific negative regulator of insulin signaling. RA domain has the beta-grasp ubiquitin-like fold with low sequence similarity to ubiquitin (Ub). Ubi is a protein modifier in eukaryotes that is involved in various cellular processes including transcriptional regulation, cell cycle control, and DNA repair in eukaryotes. A novel function of Grb14 RA domain is to interact with the nucleotide binding pocket of a cyclic nucleotide gated channel alpha subunit (CNGA1) and inhibits its activity. Grb7 and its related family members Grb10 and Grb14 share a conserved domain architecture that includes an amino-terminal proline-rich region, a central segment termed the GM region (for Grb and Mig) which includes the RA, PIR, and PH domains, and a carboxyl-terminal SH2 domain. Grb7/10/14 family proteins are phosphorylated on serine/threonine as well as tyrosine residues and are mainly localized to the cytoplasm.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697   2 TQVIKVYSEDESSRALEVPSDVTARDVCQLLILKNHYVDDNSWTLFEHLSHTGVERTVEDHELLTEVLSHWVMEEDNKLY 81
Cdd:cd16139     1 KQVIKVYSEDDTSRALEVPNDITARDVCQLFILKNHYIDDHSWTLFEHLPHIGLERIIEDHESVIEVQSNWGMETDSRLY 80

                  ....*
gi 1958763697  82 LRKNY 86
Cdd:cd16139    81 FRKNY 85

Ras-associating (RA) domain found in growth factor receptor-bound (Grb) protein 10; GRB10, also termed insulin receptor-binding protein Grb-IR, is a multi-domain cytoplasmic adaptor protein that binds to the insulin-like growth factor 1 receptor (IGF-1R) and inhibits insulin signaling. Grb10 and its related family members Grb7 and Grb14 share a conserved domain architecture that includes an amino-terminal proline-rich region, a central segment termed the GM region (for Grb and Mig) which includes the RA, PIR, and pleckstrin homology (PH) domains, and a carboxyl-terminal SH2 domain. The tandem RA and PH domains of Grb7/10/14 are also found in a second adaptor family, Rap1-interacting adaptor molecule (RIAM) and lamellipodin, which is involved in actin-cytoskeleton rearrangement. Grb7/10/14 family proteins are phosphorylated on serine/threonine as well as tyrosine residues and are mainly localized to the cytoplasm. Grb14 binds to both GTPase-defective mutant Rab5 as well as CNGA1, whereas Grb10 binds only to GTP-bound form of active Rab5.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697   2 TQVIKVYSEDESSRALEVPSDVTARDVCQLLILKNHYVDDNSWTLFEHLSHTGVERTVEDHELLTEVLSHWVMEedNKLY 81
Cdd:cd16141     2 KHIVKVFSEDGTSKVVEILADMTARDLCQLLVYKSHCVDDNSWTLVEHHPHLGLERCLEDHELVVQVQSTMGSE--SKFL 79

                          90
                  ....*....|...
gi 1958763697  82 LRKNYAKYEFFKN 94
Cdd:cd16141    80 FRKNYAKYEFFKN 92

Ras-associating (RA) domain found in growth factor receptor-bound (Grb) protein 7; GRB7, also termed B47, or epidermal growth factor receptor GRB-7, or GRB7 adapter protein, is a signal-transducing cytoplasmic adaptor protein that is co-opted by numerous tyrosine kinases involved in various cellular signaling and functions. Grb7 and its related family members Grb10 and Grb14 share a conserved domain architecture that includes an amino-terminal proline-rich region, a central segment termed the GM region (for Grb and Mig) which includes the RA, PIR, and pleckstrin homology (PH) domains, and a carboxyl-terminal SH2 domain. The tandem RA and PH domains of Grb7/10/14 are also found in a second adaptor family, Rap1-interacting adaptor molecule (RIAM) and lamellipodin, which is involved in actin-cytoskeleton rearrangement. Grb7/10/14 family proteins are phosphorylated on serine/threonine as well as tyrosine residues and are mainly localized to the cytoplasm. Grb7 could interact with activated N-Ras in transfected cells.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697   4 VIKVYSEDESSRALEVPSDVTARDVCQLLILKNHYVDDNSWTLFEHLSHTGVERTVEDHELLTEVLSHWVMEEDNKLYLR 83
Cdd:cd16140     4 VVKVYSEDGTCRSLEVTAGATARHVCEMLVQRAHCLDDESWSLVELHPHLALERCLEDHESVVEVQATWPAGGDSRFVFR 83

                  ....*
gi 1958763697  84 KNYAK 88
Cdd:cd16140    84 KNFAK 88

BPS (Between PH and SH2); The BPS (Between PH and SH2) domain, comprised of 2 beta strands and a C-terminal helix, is an approximately 45 residue region found in the adaptor proteins Grb7/10/14 that mediates inhibition of the tyrosine kinase domain of the insulin receptor by binding of the N-terminal portion of the BPS domain to the substrate peptide groove of the kinase, acting as a pseudosubstrate inhibitor.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1958763697 264 RSVSENSLVAMDFSGQKTRVIDNPTEALSVAVEEGLAWRKKGCLRL 309
Cdd:pfam08947   1 RSVSESSLVAMDFSGAGGRVIENPEEALSEAEEEGAAWRKKTLRRC 46

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 1958763697 332 QPWFHHRISRDEAQQLItrQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVedDGEVfhTLDDGHTkFTDLIQL 411
Cdd:cd09937     3 MPWFHGKISREEAERLL--QPPEDGLFLVRESTNYPGDYTLCVSFEGKVEHYRVIYR--NGKL--TIDEEEY-FENLIQL 75

                          90
                  ....*....|....*.
gi 1958763697 412 VEFYQLNKGVLPCKLK 427
Cdd:cd09937    76 VEHYTKDADGLCTRLV 91

N-terminal Src homology 2 (SH2) domain found in SH2 domains, ANK, and kinase domain (shark) proteins; These non-receptor protein-tyrosine kinases contain two SH2 domains, five ankyrin (ANK)-like repeats, and a potential tyrosine phosphorylation site in the carboxyl-terminal tail which resembles the phosphorylation site in members of the src family. Like, mammalian non-receptor protein-tyrosine kinases, ZAP-70 and syk proteins, they do not have SH3 domains. However, the presence of ANK makes these unique among protein-tyrosine kinases. Both tyrosine kinases and ANK repeats have been shown to transduce developmental signals, and SH2 domains are known to participate intimately in tyrosine kinase signaling. These tyrosine kinases are believed to be involved in epithelial cell polarity. The members of this family include the shark (SH2 domains, ANK, and kinase domain) gene in Drosophila and yellow fever mosquitos, as well as the hydra protein HTK16. Drosophila Shark is proposed to transduce intracellularly the Crumbs, a protein necessary for proper organization of ectodermal epithelia, intercellular signal. 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 1958763697 334 WFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIipvEDDGEVFHTLDDGHTKFTDLIQLVE 413
Cdd:cd10347     3 WYHGKISREVAEALLLREGGRDGLFLVRESTSAPGDYVLSLLAQGEVLHYQI---RRHGEDAFFSDDGPLIFHGLDTLIE 79

                  ..
gi 1958763697 414 FY 415
Cdd:cd10347    80 HY 81

Ras-associating (RA) domain of Mig10/RIAM/Lpd (MRL) family; MRL proteins share a common structural architecture, including a central structural unit consisting of a Ras-associating (RA) domain and a pleckstrin homology (PH) domain, an upstream coiled-coil region, and a number of polyproline motifs. RA domain-containing proteins function by interacting with Ras proteins directly or indirectly and are involved in several different functions ranging from tumor suppression to being oncoproteins. Ras proteins are small GTPases that are involved in cellular signal transduction. RA domain has the beta-grasp ubiquitin-like fold with low sequence similarity to ubiquitin (Ub). Ub is a protein modifier in eukaryotes that is involved in various cellular processes including transcriptional regulation, cell cycle control, and DNA repair in eukaryotes. RA and PH form a tandem domain pair (RA-PH), and serve tightly coordinated functions in both Ras GTPase signaling via the RA domain and membrane translocalization via the PH domain. MRL proteins have distinct functions in cell migration and adhesion, signaling, and in cell growth.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1958763697   4 VIKVYSEDESSRALEVPSDVTARDVCQLLILKNHYVDDNSWTLFEHLSHTGVERTVEDHELLTEVLSHWVMEEDNKLY 81
Cdd:cd01787     3 VVKVHMEDGSSKTLLVDERMTVRQVLKQLIEKNHCDPSVDWCLVEQYPDLYMERVFEDHEKLVENLLNWTRDSTNKLL 80

N-terminal Src homology 2 (SH2) domain found in Zeta-chain-associated protein kinase 70 (ZAP-70) and Spleen tyrosine kinase (Syk) proteins; ZAP-70 and Syk comprise a family of hematopoietic cell specific protein tyrosine kinases (PTKs) that are required for antigen and antibody receptor function. ZAP-70 is expressed in T and natural killer (NK) cells and Syk is expressed in B cells, mast cells, polymorphonuclear leukocytes, platelets, macrophages, and immature T cells. They are required for the proper development of T and B cells, immune receptors, and activating NK cells. They consist of two N-terminal Src homology 2 (SH2) domains and a C-terminal kinase domain separated from the SH2 domains by a linker or hinge region. Phosphorylation of both tyrosine residues within the Immunoreceptor Tyrosine-based Activation Motifs (ITAM; consensus sequence Yxx[LI]x(7,8)Yxx[LI]) by the Src-family PTKs is required for efficient interaction of ZAP-70 and Syk with the receptor subunits and for receptor function. ZAP-70 forms two phosphotyrosine binding pockets, one of which is shared by both SH2 domains. In Syk the two SH2 domains do not form such a phosphotyrosine-binding site. The SH2 domains here are believed to function independently. In addition, the two SH2 domains of Syk display flexibility in their relative orientation, allowing Syk to accommodate a greater variety of spacing sequences between the ITAM phosphotyrosines and singly phosphorylated non-classical ITAM ligands. This model contains the N-terminus SH2 domains of both Syk and Zap70. 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 1958763697 333 PWFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFqiiPVEDDGEVFHTLDDGHtKFTDLIQLV 412
Cdd:cd09938     2 PFFYGSITREEAEEYLKLAGMSDGLFLLRQSLRSLGGYVLSVCHGRKFHHY---TIERQLNGTYAIAGGK-AHCGPAELC 77

                          90       100
                  ....*....|....*....|
gi 1958763697 413 EFYQLNKGVLPCKLKHYCAR 432
Cdd:cd09938    78 EYHSTDLDGLVCLLRKPCNR 97

N-terminal Src homology 2 (N-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): [IVL]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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697 334 WFHHRISRDEAQQLITRQGpVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVEDDGEVFhtlddGHTKFTDLIQLVE 413
Cdd:cd10340     2 WFHPVISGIEAENLLKTRG-VDGSFLARPSKSNPGDFTLSVRRGDEVTHIKIQNTGDYYDLY-----GGEKFATLSELVQ 75

                  ....*....
gi 1958763697 414 FYQLNKGVL 422
Cdd:cd10340    76 YYMEQHGQL 84

Src homology 2 domain found in Growth factor receptor-bound protein 2 (Grb2) and similar proteins; The adaptor proteins here include homologs Grb2 in humans, Sex muscle abnormal protein 5 (Sem-5) in Caenorhabditis elegans, and Downstream of receptor kinase (drk) in Drosophila melanogaster. They are composed of one SH2 and two SH3 domains. Grb2/Sem-5/drk regulates the Ras pathway by linking the tyrosine kinases to the Ras guanine nucleotide releasing protein Sos, which converts Ras to the active GTP-bound state. The SH2 domain of Grb2/Sem-5/drk binds class II phosphotyrosyl peptides while its SH3 domain binds to Sos and Sos-derived, proline-rich peptides. Besides it function in Ras signaling, Grb2 is also thought to play a role in apoptosis. Unlike most SH2 structures in which the peptide binds in an extended conformation (such that the +3 peptide residue occupies a hydrophobic pocket in the protein, conferring a modest degree of selectivity), Grb2 forms several hydrogen bonds via main chain atoms with the side chain of +2 Asn. 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 1958763697 333 PWFHHRISRDEAQQLITRQGPvDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIpveDDGEvfhtlddGH-----TKFTD 407
Cdd:cd09941     4 PWFHGKISRAEAEEILMNQRP-DGAFLIRESESSPGDFSLSVKFGNDVQHFKVL---RDGA-------GKyflwvVKFNS 72

                  ....*....
gi 1958763697 408 LIQLVEFYQ 416
Cdd:cd09941    73 LNELVDYHR 81

Src homology 2 (SH2) domain found in the Src family of non-receptor tyrosine kinases; The Src family kinases are nonreceptor tyrosine kinases that have been implicated in pathways regulating proliferation, angiogenesis, invasion and metastasis, and bone metabolism. It is thought that transforming ability of Src is linked to its ability to activate key signaling molecules in these pathways, rather than through direct activity. As such blocking Src activation has been a target for drug companies. Src family members can be divided into 3 groups based on their expression pattern: 1) Src, Fyn, and Yes; 2) Blk, Fgr, Hck, Lck, and Lyn; and 3) Frk-related kinases Frk/Rak and Iyk/Bsk Of these, cellular c-Src is the best studied and most frequently implicated in oncogenesis. The c-Src contains five distinct regions: 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. Src exists in both active and inactive conformations. Negative regulation occurs through phosphorylation of Tyr, resulting in an intramolecular association between phosphorylated Tyr and the SH2 domain of SRC, which locks the protein in a closed conformation. Further stabilization of the inactive state occurs through interactions between the SH3 domain and a proline-rich stretch of residues within the kinase domain. Conversely, dephosphorylation of Tyr allows SRC to assume an open conformation. Full activity requires additional autophosphorylation of a Tyr residue within the catalytic domain. Loss of the negative-regulatory C-terminal segment has been shown to result in increased activity and transforming potential. Phosphorylation of the C-terminal Tyr residue by C-terminal Src kinase (Csk) and Csk homology kinase results in increased intramolecular interactions and consequent Src inactivation. Specific phosphatases, protein tyrosine phosphatase a (PTPa) and the SH-containing phosphatases SHP1/SHP2, have also been shown to take a part in Src activation. Src is also activated by direct binding of focal adhesion kinase (Fak) and Crk-associated substrate (Cas) to the SH2 domain. SRC activity can also be regulated by numerous receptor tyrosine kinases (RTKs), such as Her2, epidermal growth factor receptor (EGFR), fibroblast growth factor receptor, platelet-derived growth factor receptor (PDGFR), and vascular endothelial growth factor receptor (VEGFR). 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 1958763697 331 SQPWFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPRTFVLSM-----SHGQKIKHFQIIPVEDDGEVFHTlddgHTKF 405
Cdd:cd09933     2 AEEWFFGKIKRKDAEKLLLAPGNPRGTFLIRESETTPGAYSLSVrdgddARGDTVKHYRIRKLDNGGYYITT----RATF 77

                          90       100
                  ....*....|....*....|.
gi 1958763697 406 TDLIQLVEFYQLNKGVLPCKL 426
Cdd:cd09933    78 PTLQELVQHYSKDADGLCCRL 98

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.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1958763697 333 PWFHHRISRDEAQQLITRQGPvDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVEDD-----GEVFHTLDD 400
Cdd:cd10354     1 IWFHGKISREEAYNMLVKVGG-PGSFLVRESDNTPGDYSLSFRVNEGIKHFKIIPTGNNqfmmgGRYFSSLDD 72

C-terminal Src homology 2 (SH2) domain found in SH2 domains, ANK, and kinase domain (shark) proteins; These non-receptor protein-tyrosine kinases contain two SH2 domains, five ankyrin (ANK)-like repeats, and a potential tyrosine phosphorylation site in its carboxyl-terminal tail which resembles the phosphorylation site in members of the src family. Like, mammalian non-receptor protein-tyrosine kinases, ZAP-70 and syk proteins, they do not have SH3 domains. However, the presence of ANK makes these unique among protein-tyrosine kinases. Both tyrosine kinases and ANK repeats have been shown to transduce developmental signals, and SH2 domains are known to participate intimately in tyrosine kinase signaling. These tyrosine kinases are believed to be involved in epithelial cell polarity. The members of this family include the shark (SH2 domains, ANK, and kinase domain) gene in Drosophila and yellow fever mosquitos, as well as the hydra protein HTK16. Drosophila Shark is proposed to transduce intracellularly the Crumbs, a protein necessary for proper organization of ectodermal epithelia, intercellular signal. 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 1958763697 334 WFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIipvEDDGEVFHTLDDGhTKFTDLIQLVE 413
Cdd:cd10348     2 WLHGALDRNEAVEILKQKADADGSFLVRYSRRRPGGYVLTLVYENHVYHFEI---QNRDDKWFYIDDG-PYFESLEHLIE 77

                  ..
gi 1958763697 414 FY 415
Cdd:cd10348    78 HY 79

Ras-associating (RA) domain found in Rap1-GTP-interacting adapter molecule (RIAM); RIAM, also termed amyloid beta A4 precursor protein-binding family B member 1-interacting protein, or APBB1-interacting protein 1, or proline-rich EVH1 ligand 1 (PREL-1), or proline-rich protein 73, or retinoic acid-responsive proline-rich protein 1 (RARP-1), is a member of MRL (Mig10/RIAM/Lpd) family proteins that regulates cell migration and promote lamellipodia protrusion in fibroblast by interacting with Ena/VASP proteins. RIAM regulates cell migration and mediates Rap1-induced cell adhesion. MRL proteins share a common structural architecture, including a central structural unit consisting of an RA domain and a pleckstrin homology (PH) domain, an upstream coiled-coil region, and a number of polyproline motifs. RA domain-containing proteins function by interacting with Ras proteins directly or indirectly and are involved in several different functions ranging from tumor suppression to being oncoproteins. RA domain has the beta-grasp ubiquitin-like fold with low sequence similarity to ubiquitin (Ub). Ub is a protein modifier in eukaryotes that is involved in various cellular processes including transcriptional regulation, cell cycle control, and DNA repair in eukaryotes. RIAM also contains a helical region at the amino terminus for talin binding. RA and PH form a tandem domain pair (RA-PH), and serve tightly coordinated functions in both Ras GTPase signaling via the RA domain and membrane translocalization via the PH domain.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697   4 VIKVYSEDESSRALEVPSDVTARDVCQLLILKNHYVDDNSWTLFEHLSHTGVERTVEDHELLTEVLSHWVMEEDNKLYLR 83
Cdd:cd16137     4 VVKVHMNDSSTKTLMVDERQTVRDVLDNLFEKTHCDCNVDWCLYEVNPELQIERFFEDHENVVEVLSDWTRDSENKVLFL 83

                  ....*.
gi 1958763697  84 KNYAKY 89
Cdd:cd16137    84 EKKEKY 89

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        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697 334 WFHHRISRDEAQQLItrQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVEDDGEVFHTLDDGHTKFTDLIQLVE 413
Cdd:cd09926     9 WYFGPMSRQEAQELL--QGQRHGVFLVRDSSTIPGDYVLSVSENSRVSHYIINSLGQPAPNQSRYRIGDQEFDDLPALLE 86

                          90
                  ....*....|....*..
gi 1958763697 414 FYQLnkgvlpcklkHYC 430
Cdd:cd09926    87 FYKL----------HYL 93

Src homology 2 (SH2) domain found in feline sarcoma, Fujinami poultry sarcoma, and fes-related (Fes/Fps/Fer) proteins; The Fps family consists of members Fps/Fes and Fer/Flk/Tyk3. They are cytoplasmic protein-tyrosine kinases implicated in signaling downstream from cytokines, growth factors and immune receptors. Fes/Fps/Fer contains three coiled-coil regions, an SH2 (Src-homology-2) and a TK (tyrosine kinase catalytic) domain signature. Members here include: Fps/Fes, Fer, Kin-31, and 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 1958763697 329 HRSQPWFHHRISRDEAQQLITRQGpvDgvFLVRDSQ---SNPRTFVLSMSHGQKIKHFQIipVEDDGEVFHTLDdghTKF 405
Cdd:cd10361     3 LENEPYYHGLLPREDAEELLKNDG--D--FLVRKTEpkgGGKRKLVLSVRWDGKIRHFVI--NRDDGGKYYIEG---KSF 73

                          90
                  ....*....|....
gi 1958763697 406 TDLIQLVEFYQLNK 419
Cdd:cd10361    74 KSISELINYYQKTK 87

Pleckstrin homology domain; Domain commonly found in eukaryotic signalling proteins. The domain family possesses multiple functions including the abilities to bind inositol phosphates, and various proteins. PH domains have been found to possess inserted domains (such as in PLC gamma, syntrophins) and to be inserted within other domains. Mutations in Brutons tyrosine kinase (Btk) within its PH domain cause X-linked agammaglobulinaemia (XLA) in patients. Point mutations cluster into the positively charged end of the molecule around the predicted binding site for phosphatidylinositol lipids.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697  130 PEIHGFLHAKEQ-GKKSWKKAYFFLRRSGLYFSTKGTSKEPRHLQFFSEFSTSNVYMSLAGKKKhgaptPYGFCFKPTka 208
Cdd:smart00233   1 VIKEGWLYKKSGgGKKSWKKRYFVLFNSTLLYYKSKKDKKSYKPKGSIDLSGCTVREAPDPDSS-----KKPHCFEIK-- 73

                           90       100
                   ....*....|....*....|....*....
gi 1958763697  209 GGPRDLKMLCAEEDQSRMCWVTAIRLLKY 237
Cdd:smart00233  74 TSDRKTLLLQAESEEEREKWVEALRKAIA 102

Src homology 2 (SH2) domain found in Src-related kinase lacking C-terminal regulatory tyrosine and N-terminal myristoylation sites (srm); Srm is a nonreceptor protein kinase that has two SH2 domains, a SH3 domain, and a kinase domain with a tyrosine residue for autophosphorylation. However it lacks an N-terminal glycine for myristoylation and a C-terminal tyrosine which suppresses kinase activity when phosphorylated. Srm is most similar to members of the Tec family who other members include: Tec, Btk/Emb, and Itk/Tsk/Emt. However Srm differs in its N-terminal unique domain it being much smaller than in the Tec family and is closer to Src. Srm is thought to be a new family of nonreceptor tyrosine kinases that may be redundant in 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 1958763697 333 PWFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIpVEDDGEVFhtLDDGHTkFTDLIQLV 412
Cdd:cd10360     1 PWYFSGISRTQAQQLLLSPPNEPGAFLIRPSESSLGGYSLSVRAQAKVCHYRIC-MAPSGSLY--LQKGRL-FPGLEELL 76

                  ...
gi 1958763697 413 EFY 415
Cdd:cd10360    77 AYY 79

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 1958763697 332 QPWFHHRISRDEAQQLITrqGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHfqiIPVEDDGEVFHTLDDGhTKFTDLIQL 411
Cdd:cd09940     5 FLWFVGEMERDTAENRLE--NRPDGTYLVRVRPQGETQYALSIKYNGDVKH---MKIEQRSDGLYYLSES-RHFKSLVEL 78

                  ....*..
gi 1958763697 412 VEFYQLN 418
Cdd:cd09940    79 VNYYERN 85

C-terminal Src homology 2 (SH2) domain found in Spleen tyrosine kinase (Syk) proteins; ZAP-70 and Syk comprise a family of hematopoietic cell specific protein tyrosine kinases (PTKs) that are required for antigen and antibody receptor function. ZAP-70 is expressed in T and natural killer (NK) cells and Syk is expressed in B cells, mast cells, polymorphonuclear leukocytes, platelets, macrophages, and immature T cells. They are required for the proper development of T and B cells, immune receptors, and activating NK cells. They consist of two N-terminal Src homology 2 (SH2) domains and a C-terminal kinase domain separated from the SH2 domains by a linker or hinge region. Phosphorylation of both tyrosine residues within the Immunoreceptor Tyrosine-based Activation Motifs (ITAM; consensus sequence Yxx[LI]x(7,8)Yxx[LI]) by the Src-family PTKs is required for efficient interaction of ZAP-70 and Syk with the receptor subunits and for receptor function. ZAP-70 forms two phosphotyrosine binding pockets, one of which is shared by both SH2 domains. In Syk the two SH2 domains do not form such a phosphotyrosine-binding site. The SH2 domains here are believed to function independently. In addition, the two SH2 domains of Syk display flexibility in their relative orientation, allowing Syk to accommodate a greater variety of spacing sequences between the ITAM phosphotyrosines and singly phosphorylated non-classical ITAM ligands. This model contains the C-terminus SH2 domains of Syk. 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 1958763697 333 PWFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPrTFVLSMSHGQKIKHFQIipvEDDGEVFHTLDDGhTKFTDLIQLV 412
Cdd:cd10401     4 PWFHGKISREESEQILLIGSKTNGKFLIRERDNNG-SYALCLLHDGKVLHYRI---DKDKTGKLSIPDG-KKFDTLWQLV 78

                  ...
gi 1958763697 413 EFY 415
Cdd:cd10401    79 EHY 81

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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763697 332 QPWFHHRISRDEAQQLITRQGpVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIipveDDGEVFHTLddGHTKFTDLIQL 411
Cdd:cd10408     1 NPWYYGKVTRHQAEMALNERG-NEGDFLIRDSESSPNDFSVSLKAQGKNKHFKV----QLKECVYCI--GQRKFSSMEEL 73

                  ....*
gi 1958763697 412 VEFYQ 416
Cdd:cd10408    74 VEHYK 78

Src homology 2 (SH2) domain found in the Src oncogene at 42A (Src42); Src42 is a member of the Src non-receptor type tyrosine kinase family of proteins. The integration of receptor tyrosine kinase-induced RAS and Src42 signals by Connector eNhancer of KSR (CNK) as a two-component input is essential for RAF activation in Drosophila. Src42 is present in a wide variety of organisms including: California sea hare, pea aphid, yellow fever mosquito, honey bee, Panamanian leafcutter ant, and sea urchin. Src42 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. Like the other members of the Src family the SH2 domain in addition to binding the target, also plays an autoinhibitory role by binding to its C-terminal tail. 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 1958763697 331 SQPWFHHRISRDEAQQLITRQGPVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIipveddgevfHTLDDG------HTK 404
Cdd:cd10370     2 AEPWYFGKIKRIEAEKKLLLPENEHGAFLIRDSESRHNDYSLSVRDGDTVKHYRI----------RQLDEGgffiarRTT 71