Src homology 2 (SH2) domain found in SH2 adaptor protein C (SHC); SHC is involved in a wide variety of pathways including regulating proliferation, angiogenesis, invasion and metastasis, and bone metabolism. An adapter protein, SHC has been implicated in Ras activation following the stimulation of a number of different receptors, including growth factors [insulin, epidermal growth factor (EGF), nerve growth factor, and platelet derived growth factor (PDGF)], cytokines [interleukins 2, 3, and 5], erythropoietin, and granulocyte/macrophage colony-stimulating factor, and antigens [T-cell and B-cell receptors]. SHC has been shown to bind to tyrosine-phosphorylated receptors, and receptor stimulation leads to tyrosine phosphorylation of SHC. Upon phosphorylation, SHC interacts with another adapter protein, Grb2, which binds to the Ras GTP/GDP exchange factor mSOS which leads to Ras activation. SHC is composed of an N-terminal domain that interacts with proteins containing phosphorylated tyrosines, a (glycine/proline)-rich collagen-homology domain that contains the phosphorylated binding site, and a C-terminal SH2 domain. SH2 has been shown to interact with the tyrosine-phosphorylated receptors of EGF and PDGF and with the tyrosine-phosphorylated C chain of the T-cell receptor, providing one of the mechanisms of T-cell-mediated Ras activation. 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 194239662 480 AEQLRGEPWFHGKLSRREAEALLQLNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLVDPEGVVRTKDHRFESVSHLISYH 559
Cdd:cd09925    1 AEQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYH 80

                         90       100
                 ....*....|....*....|....
gi 194239662 560 MDNHLPIISAGSELCLQQPVERKL 583
Cdd:cd09925   81 VTNGLPIISEGSELHLRRPVRRPA 104

Src homology 2 (SH2) domain found in SH2 adaptor protein C (SHC); SHC is involved in a wide variety of pathways including regulating proliferation, angiogenesis, invasion and metastasis, and bone metabolism. An adapter protein, SHC has been implicated in Ras activation following the stimulation of a number of different receptors, including growth factors [insulin, epidermal growth factor (EGF), nerve growth factor, and platelet derived growth factor (PDGF)], cytokines [interleukins 2, 3, and 5], erythropoietin, and granulocyte/macrophage colony-stimulating factor, and antigens [T-cell and B-cell receptors]. SHC has been shown to bind to tyrosine-phosphorylated receptors, and receptor stimulation leads to tyrosine phosphorylation of SHC. Upon phosphorylation, SHC interacts with another adapter protein, Grb2, which binds to the Ras GTP/GDP exchange factor mSOS which leads to Ras activation. SHC is composed of an N-terminal domain that interacts with proteins containing phosphorylated tyrosines, a (glycine/proline)-rich collagen-homology domain that contains the phosphorylated binding site, and a C-terminal SH2 domain. SH2 has been shown to interact with the tyrosine-phosphorylated receptors of EGF and PDGF and with the tyrosine-phosphorylated C chain of the T-cell receptor, providing one of the mechanisms of T-cell-mediated Ras activation. 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 194239662 480 AEQLRGEPWFHGKLSRREAEALLQLNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLVDPEGVVRTKDHRFESVSHLISYH 559
Cdd:cd09925    1 AEQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYH 80

                         90       100
                 ....*....|....*....|....
gi 194239662 560 MDNHLPIISAGSELCLQQPVERKL 583
Cdd:cd09925   81 VTNGLPIISEGSELHLRRPVRRPA 104

Phosphotyrosine-binding domain, phosphotyrosine-interaction (PI) domain; PTB/PI domain structure similar to those of pleckstrin homology (PH) and IRS-1-like PTB domains.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662   157 GPGVSYLVRYMGCVEVLQSMRaldfntrTQVTREAISLVCEAVPGAKGATRrrkpcsrplssilgrsnlkfagmPITLTV 236
Cdd:smart00462   1 GSGVSFRVKYLGSVEVPEARG-------LQVVQEAIRKLRAAQGSEKKEPQ-----------------------KVILSI 50

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662   237 STSSLNLMAADCKQIIANHHMQSISFAsGGDPDTAEYVAYVAKDPVNQR-ACHILECpEGLAQDVISTIGQAFELRFKQY 315
Cdd:smart00462  51 SSRGVKLIDEDTKAVLHEHPLRRISFC-AVGPDDLDVFGYIARDPGSSRfACHVFRC-EKAAEDIALAIGQAFQLAYELK 128

                   ..
gi 194239662   316 LR 317
Cdd:smart00462 129 LK 130

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 194239662   486 EPWFHGKLSRREAEALLQLN--GDFLVRESTTTPGQYVLTGLQSGQPKHLLL-VDPEGVVR-TKDHRFESVSHLISYHMD 561
Cdd:smart00252   1 QPWYHGFISREEAEKLLKNEgdGDFLVRDSESSPGDYVLSVRVKGKVKHYRIrRNEDGKFYlEGGRKFPSLVELVEHYQK 80

                   ....
gi 194239662   562 NHLP 565
Cdd:smart00252  81 NSLG 84

Src homology 2 (SH2) domain found in SH2 adaptor protein C (SHC); SHC is involved in a wide variety of pathways including regulating proliferation, angiogenesis, invasion and metastasis, and bone metabolism. An adapter protein, SHC has been implicated in Ras activation following the stimulation of a number of different receptors, including growth factors [insulin, epidermal growth factor (EGF), nerve growth factor, and platelet derived growth factor (PDGF)], cytokines [interleukins 2, 3, and 5], erythropoietin, and granulocyte/macrophage colony-stimulating factor, and antigens [T-cell and B-cell receptors]. SHC has been shown to bind to tyrosine-phosphorylated receptors, and receptor stimulation leads to tyrosine phosphorylation of SHC. Upon phosphorylation, SHC interacts with another adapter protein, Grb2, which binds to the Ras GTP/GDP exchange factor mSOS which leads to Ras activation. SHC is composed of an N-terminal domain that interacts with proteins containing phosphorylated tyrosines, a (glycine/proline)-rich collagen-homology domain that contains the phosphorylated binding site, and a C-terminal SH2 domain. SH2 has been shown to interact with the tyrosine-phosphorylated receptors of EGF and PDGF and with the tyrosine-phosphorylated C chain of the T-cell receptor, providing one of the mechanisms of T-cell-mediated Ras activation. 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 194239662 480 AEQLRGEPWFHGKLSRREAEALLQLNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLVDPEGVVRTKDHRFESVSHLISYH 559
Cdd:cd09925    1 AEQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYH 80

                         90       100
                 ....*....|....*....|....
gi 194239662 560 MDNHLPIISAGSELCLQQPVERKL 583
Cdd:cd09925   81 VTNGLPIISEGSELHLRRPVRRPA 104

Phosphotyrosine-binding domain, phosphotyrosine-interaction (PI) domain; PTB/PI domain structure similar to those of pleckstrin homology (PH) and IRS-1-like PTB domains.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662   157 GPGVSYLVRYMGCVEVLQSMRaldfntrTQVTREAISLVCEAVPGAKGATRrrkpcsrplssilgrsnlkfagmPITLTV 236
Cdd:smart00462   1 GSGVSFRVKYLGSVEVPEARG-------LQVVQEAIRKLRAAQGSEKKEPQ-----------------------KVILSI 50

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662   237 STSSLNLMAADCKQIIANHHMQSISFAsGGDPDTAEYVAYVAKDPVNQR-ACHILECpEGLAQDVISTIGQAFELRFKQY 315
Cdd:smart00462  51 SSRGVKLIDEDTKAVLHEHPLRRISFC-AVGPDDLDVFGYIARDPGSSRfACHVFRC-EKAAEDIALAIGQAFQLAYELK 128

                   ..
gi 194239662   316 LR 317
Cdd:smart00462 129 LK 130

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 194239662 481 EQLRGEPWFHGKLSRREAEALLQLNGDFLVRES---TTTPGQYVLTGLQSGQPKHLLL-VDPEGVVRTKDHRFESVSHLI 556
Cdd:cd10361    1 KDLENEPYYHGLLPREDAEELLKNDGDFLVRKTepkGGGKRKLVLSVRWDGKIRHFVInRDDGGKYYIEGKSFKSISELI 80

                         90
                 ....*....|
gi 194239662 557 SYHMDNHLPI 566
Cdd:cd10361   81 NYYQKTKEPI 90

Src homology 2 (SH2) domain in the Breast Cancer Anti-estrogen Resistance protein 3; BCAR3 is part of a growing family of guanine nucleotide exchange factors is responsible for activation of Ras-family GTPases, including Sos1 and 2, GRF1 and 2, CalDAG-GEF/GRP1-4, C3G, cAMP-GEF/Epac 1 and 2, PDZ-GEFs, MR-GEF, RalGDS family members, RalGPS, RasGEF, Smg GDS, and phospholipase C(epsilon). 12102558 21262352 BCAR3 binds to the carboxy-terminus of BCAR1/p130Cas, a focal adhesion adapter protein. Over expression of BCAR1 (p130Cas) and BCAR3 induces estrogen independent growth in normally estrogen-dependent cell lines. They have been linked to resistance to anti-estrogens in breast cancer, Rac activation, and cell motility, though the BCAR3/p130Cas complex is not required for this activity in BCAR3. Many BCAR3-mediated signaling events in epithelial and mesenchymal cells are independent of p130Cas association. Structurally these proteins contain a single SH2 domain upstream of their RasGEF domain, which is responsible for the ability of BCAR3 to enhance p130Cas over-expression-induced migration. 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 194239662 481 EQLRGEPWFHGKLSRREAEALLQLNGDFLVRESTTTPGQYVLTGLQSGQPKHLLL---VDPEGVVRTK------DHRFES 551
Cdd:cd10337    1 EDLRSHAWYHGRIPRQVAESLVQREGDFLVRDSLSSPGDYVLTCRWKGQPLHFKInrvVLRPSEAYTRvqyqfeDEQFDS 80

                         90       100       110
                 ....*....|....*....|....*....|
gi 194239662 552 VSHLISYHMDNHLPiISAGSELCLQQPVER 581
Cdd:cd10337   81 IPALVHFYVGNRRP-ISQASGAIISRPVNR 109

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662 160 VSYLVRYMGCVEVLQSMRAldfntrtQVTREAISLVceavpgakgatrrrkpcsrplssILGRSNLKFAGMPITLTVSTS 239
Cdd:cd00934    1 ASFQVKYLGSVEVGSSRGV-------DVVEEALKAL-----------------------AAALKSSKRKPGPVLLEVSSK 50

                         90       100       110       120       130       140       150
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 194239662 240 SLNLMAADCKQIIANHHMQSISFaSGGDPDTAEYVAYVAKDP-VNQRACHILECP-EGLAQDVISTIGQAF 308
Cdd:cd00934   51 GVKLLDLDTKELLLRHPLHRISY-CGRDPDNPNVFAFIAGEEgGSGFRCHVFQCEdEEEAEEILQAIGQAF 120

Src homology 2 (SH2) domain found in SH2B adapter protein family; The SH2B adapter protein family has 3 members: SH2B1 (SH2-B, PSM), SH2B2 (APS), and SH2B3 (Lnk). SH2B family members contain a pleckstrin homology domain, at least one dimerization domain, and a C-terminal SH2 domain which binds to phosphorylated tyrosines in a variety of tyrosine kinases. SH2B1 and SH2B2 function in signaling pathways found downstream of growth hormone receptor and receptor tyrosine kinases, including the insulin, insulin-like growth factor-I (IGF-I), platelet-derived growth factor (PDGF), nerve growth factor, hepatocyte growth factor, and fibroblast growth factor receptors. SH2B2beta, a new isoform of SH2B2, is an endogenous inhibitor of SH2B1 and/or SH2B2 (SH2B2alpha), negatively regulating insulin signaling and/or JAK2-mediated cellular responses. SH2B3 negatively regulates lymphopoiesis and early hematopoiesis. The lnk-deficiency results in enhanced production of B cells, and expansion as well as enhanced function of hematopoietic stem cells (HSCs), demonstrating negative regulatory functions of Sh2b3/Lnk in cytokine signaling. Sh2b3/Lnk also functions in responses controlled by cell adhesion and in crosstalk between integrin- and cytokine-mediated 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 194239662 483 LRGEPWFHGKLSRREAEALLQLNGD-----FLVRESTTTPGQYVLTGLQSGQPKHL-LLVDPEGVVRTKDHRFESVSHLI 556
Cdd:cd10346    5 LSEYPWFHGTLSRSDAAQLVLHSGAdghgvFLVRQSETRRGEFVLTFNFQGRAKHLrLTLNEKGQCRVQHLWFPSIFDML 84

                         90
                 ....*....|..
gi 194239662 557 SYHMDNHLPIIS 568
Cdd:cd10346   85 EHFRQNPIPLES 96

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 194239662 485 GEPWFHGKLS--RREAEALLQL-----NGDFLVRESTTTPGQYVLTGLQSGQPKH----LLLVDPEGVVRTKDHR-FESV 552
Cdd:cd10341    3 TEPWFHGKLGdgRDEAEKLLLEyceggDGTFLVRESETFVGDYTLSFWRNGKVQHcrirSRQENGEKKYYLTDNLvFDSL 82

                         90
                 ....*....|..
gi 194239662 553 SHLISYHMDNHL 564
Cdd:cd10341   83 YELIDYYRQNPL 94

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 194239662 487 PWFHGKLSRREAEALLQLNGD--FLVRESTTTPGQYVLTGLQSGQPKHLLLVDPEGVVrTKDHR--FESVSHLIS-YHMD 561
Cdd:cd09937    4 PWFHGKISREEAERLLQPPEDglFLVRESTNYPGDYTLCVSFEGKVEHYRVIYRNGKL-TIDEEeyFENLIQLVEhYTKD 82

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 194239662 488 WFHGKLSRREAEALLQLNGD----FLVRESTTTPGQYVLTGLQSGQPKHLllvdpegVVRTKDHR---------FESVSH 554
Cdd:cd10348    2 WLHGALDRNEAVEILKQKADadgsFLVRYSRRRPGGYVLTLVYENHVYHF-------EIQNRDDKwfyiddgpyFESLEH 74

                 ....*.
gi 194239662 555 LISYHM 560
Cdd:cd10348   75 LIEHYT 80

Ankyrin repeat and sterile alpha motif (SAM) domain-containing (Anks) protein family Phosphotyrosine-binding (PTB) domain; Both AIDA-1b (AbetaPP intracellular domain-associated protein 1b) and Odin (also known as ankyrin repeat and sterile alpha motif domain-containing 1A; ANKS1A) belong to the Anks protein family. Both of these family members interacts with the EphA8 receptor. Ank members consists of ankyrin repeats, a SAM domain and a C-terminal PTB domain which is crucial for interaction with the juxtamembrane (JM) region of EphA8. PTB domains are classified into three groups, namely, phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains of which the Anks PTB is a member. PTB domains have a common PH-like fold and are found in various eukaryotic signaling molecules. This domain was initially shown to binds peptides with a NPXY motif with differing requirements for phosphorylation of the tyrosine, although more recent studies have found that some types of PTB domains can bind to peptides lack tyrosine residues altogether. In contrast to SH2 domains, which recognize phosphotyrosine and adjacent carboxy-terminal residues, PTB-domain binding specificity is conferred by residues amino-terminal to the phosphotyrosine. PTB domains are classified into three groups: phosphotyrosine-dependent Shc-like, phosphotyrosine-dependent IRS-like, and phosphotyrosine-independent Dab-like PTB domains. This cd is part of the Dab-like subgroup.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662 148 WLHPNDKVMGPGVSYLVRYMGCVEVLqsmraldfNTR-TQVTREAIslvceavpgAKGATRRRKPCSRPlssilgrsnlk 226
Cdd:cd01274    3 WRHSPEKLITGSVNYEAHYLGSTEIK--------ELRgTESTKKAI---------QKLKKSTREMKKIP----------- 54

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662 227 fagmPITLTVSTSSLNLMAADCKQIIANHHMQSISFASGgDPDTAEYVAYVAKDPVNQRA-CHILECPE-GLAQDVISTI 304
Cdd:cd01274   55 ----TIILSISYKGVKFIDATTKNLICEHEIRNISCACQ-DPEDLNTFAYITKDLKTDHHyCHVFCVLTvDLATEIILTL 129

                        170
                 ....*....|...
gi 194239662 305 GQAFELRFKQYLR 317
Cdd:cd01274  130 GQAFEVAYQLALR 142

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
                 ....*....|....*....|....*....|....*....|..
gi 194239662 486 EPWFHGKLSRREAEALLQL----NGDFLVRESTTTPGQYVLT 523
Cdd:cd09933    3 EEWFFGKIKRKDAEKLLLApgnpRGTFLIRESETTPGAYSLS 44

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. There are 3 members of the Grb7 family of proteins: Grb7, 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. Grb14 binds to Fibroblast Growth Factor Receptor (FGFR). Grb10 has been shown to interact with many different proteins, including the insulin and IGF1 receptors, platelet-derived growth factor (PDGF) receptor-beta, Ret, Kit, Raf1 and MEK1, and Nedd4. 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 194239662 484 RGEPWFHGKLSRREAEALLQ----LNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLV---DPEGVVRTKDH---RFESVS 553
Cdd:cd09944    3 RSQPWFHGGISRDEAARLIRqqglVDGVFLVRESQSNPGAFVLSLKHGQKIKHYQIIpieDEGQWYFTLDDgvtKFYDLL 82

                         90       100
                 ....*....|....*....|....*....
gi 194239662 554 HLISYHMDNhlpiisAGS-ELCLQQPVER 581
Cdd:cd09944   83 QLVEFYQLN------AGSlPTRLKHYCTR 105

Src homology 2 (SH2) domain found in alpha2-chimerin and beta2-chimerin proteins; Chimerins are a family of phorbol ester- and diacylglycerol-responsive GTPase-activating proteins. Alpha1-chimerin (formerly known as n-chimerin) and alpha2-chimerin are alternatively spliced products of a single gene, as are beta1- and beta2-chimerin. alpha1- and beta1-chimerin have a relatively short N-terminal region that does not encode any recognizable domains, whereas alpha2- and beta2-chimerin both include a functional SH2 domain that can bind to phosphotyrosine motifs within receptors. All of the isoforms contain a GAP domain with specificity in vitro for Rac1 and a diacylglycerol (DAG)-binding C1 domain which allows them to translocate to membranes in response to DAG signaling and anchors them in close proximity to activated Rac. Other C1 domain-containing diacylglycerol receptors including: PKC, Munc-13 proteins, phorbol ester binding scaffolding proteins involved in Ca2+-stimulated exocytosis, and RasGRPs, diacylglycerol-activated guanine-nucleotide exchange factors (GEFs) for Ras and Rap1. 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 194239662 489 FHGKLSRREAEALLQLNGD--FLVRESTTTPGQYVLTGLQSGQPKHL-LLVDPEGVV-RTKDHRFESVSH-----LISYH 559
Cdd:cd10352    9 YHGLISREEAEQLLSGASDgsYLIRESSRDDGYYTLSLRFNGKVKNYkLYYDGKNHYhYVGEKRFDTIHDlvadgLITLY 88

                 ...
gi 194239662 560 MDN 562
Cdd:cd10352   89 MET 91

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 194239662 487 PWFHGKLSRREAEALLQLN---GDFLVRESTTTPGQYVLTGLQSGQPKHLLLV-DPEGVVRTKDHRFESVSHLISYH 559
Cdd:cd10354    1 IWFHGKISREEAYNMLVKVggpGSFLVRESDNTPGDYSLSFRVNEGIKHFKIIpTGNNQFMMGGRYFSSLDDVIDRY 77

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 194239662 482 QLRGEPWFHGKLSRREAEALL--QLNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLVDPEGVVR-TKDHRFESVSHLISY 558
Cdd:cd09942    3 SLQEAEWYWGDISREEVNEKMrdTPDGTFLVRDASTMKGDYTLTLRKGGNNKLIKIFHRDGKYGfSDPLTFNSVVELINY 82

                         90       100
                 ....*....|....*....|...
gi 194239662 559 HMDNHLPIISAGSELCLQQPVER 581
Cdd:cd09942   83 YRNNSLAEYNRKLDVKLLYPVSR 105

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 194239662 487 PWFHGKLSRREAEALL---QLNGDFLVRESTTTPGQYVLTGLQSGQPKHL-LLVDPEGVVRTKDHRFESVSHLISYHMDN 562
Cdd:cd09941    4 PWFHGKISRAEAEEILmnqRPDGAFLIRESESSPGDFSLSVKFGNDVQHFkVLRDGAGKYFLWVVKFNSLNELVDYHRTT 83

                 .
gi 194239662 563 H 563
Cdd:cd09941   84 S 84

Src homology 2 (SH2) domain found in tyrosine kinase sarcoma (Src); Src is a member of the Src non-receptor type tyrosine kinase family of proteins. Src is thought to play a role in the regulation of embryonic development and cell growth. Members here include v-Src and c-Src. v-Src lacks the C-terminal inhibitory phosphorylation site and is therefore constitutively active as opposed to normal cellular src (c-Src) which is only activated under certain circumstances where it is required (e.g. growth factor signaling). v-Src is an oncogene whereas c-Src is a proto-oncogene. c-Src consists of three domains, an N-terminal SH3 domain, a central SH2 domain and a tyrosine kinase domain. The SH2 and SH3 domains work together in the auto-inhibition of the kinase domain. The phosphorylation of an inhibitory tyrosine near the c-terminus of the protein produces a binding site for the SH2 domain which then facilitates binding of the SH3 domain to a polyproline site within the linker between the SH2 domain and the kinase domain. Binding of the SH3 domain inactivates the enzyme. This allows for multiple mechanisms for c-Src activation: dephosphorylation of the C-terminal tyrosine by a protein tyrosine phosphatase, binding of the SH2 domain by a competitive phospho-tyrosine residue, or competitive binding of a polyproline binding site to the SH3 domain. Unlike most other Src members Src lacks cysteine residues in the SH4 domain that undergo palmitylation. Serine and threonine phosphorylation sites have also been identified in the unique domains of Src and are believed to modulate protein-protein interactions or regulate catalytic activity. Alternatively spliced forms of Src, which contain 6- or 11-amino acid insertions in the SH3 domain, are expressed in CNS neurons. c-Src 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 194239662 484 RGEPWFHGKLSRREAEALLqLN-----GDFLVRESTTTPGQYVLTGLQSGQPKHLLL-------VDPEGVVRTKDHRFES 551
Cdd:cd10365    1 QAEEWYFGKITRRESERLL-LNaenprGTFLVRESETTKGAYCLSVSDFDNAKGLNVkhykirkLDSGGFYITSRTQFNS 79

                 ....*...
gi 194239662 552 VSHLISYH 559
Cdd:cd10365   80 LQQLVAYY 87

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662 225 LKFAGMPITLTVSTSSLNLMAADCKQIIANHHMQSISFaSGGDPDTAEYVAYVAKDPVNQRA-CHILECPEGlAQDVIST 303
Cdd:cd13161   33 LKLKPKPVVLVVSSEGIRVVERLTGEVLTNVPIKDISF-VTVDPKDKKLFAFISHDPRLGRItCHVFRCKRG-AQEICDT 110

                 ....*.
gi 194239662 304 IGQAFE 309
Cdd:cd13161  111 IAEAFK 116

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 194239662 488 WFHGKLSRREAEALLQ---LNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLVDPEGVVRTKDHRFESVSHLISYHmdNHL 564
Cdd:cd10409    3 WYYGNVTRHQAECALNergVEGDFLIRDSESSPSDFSVSLKAVGKNKHFKVQLVDNVYCIGQRRFNSMDELVEHY--KKA 80

                         90
                 ....*....|....*...
gi 194239662 565 PIISA--GSELCLQQPVE 580
Cdd:cd10409   81 PIFTSehGEKLYLVKALQ 98

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 194239662 487 PWFHGKLSRREAEALLQ---LNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLVDPEGVVRTKDHRFESVSHLISYHmdNH 563
Cdd:cd10408    2 PWYYGKVTRHQAEMALNergNEGDFLIRDSESSPNDFSVSLKAQGKNKHFKVQLKECVYCIGQRKFSSMEELVEHY--KK 79

                         90
                 ....*....|....*...
gi 194239662 564 LPIISA--GSELCLQQPV 579
Cdd:cd10408   80 APIFTSeqGEKLYLIKAL 97

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
                 ....*....|....*....|....*....|....*..
gi 194239662 488 WFHGKLSRREAEALL--QLNGDFLVRESTTTPGQYVL 522
Cdd:cd09926    9 WYFGPMSRQEAQELLqgQRHGVFLVRDSSTIPGDYVL 45

Src homology 2 (SH2) domain found in the growth factor receptor bound, subclass 14 (Grb14) proteins; The Grb family binds to the epidermal growth factor receptor (EGFR, erbB1) via their SH2 domains. Grb14 is part of the Grb7 family of proteins which also includes Grb7, 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. Grb14 binds to Fibroblast Growth Factor Receptor (FGFR) and weakly to the erbB2 receptor. 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 194239662 484 RGEPWFHGKLSRREAEALL----QLNGDFLVRESTTTPGQYVLTGLQSGQPKHLLLVDPE 539
Cdd:cd10414    3 RSQPWFHHKISRDEAQRLIiqqgLVDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVE 62

Src homology 2 domain found in the SH2 domain containing protein 2A and 7 (SH2D2A and SH2D7); SH2D2A and SH7 both contain a single 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 194239662 487 PWFHGKLSRREAEALL--QLNGDFLVRESTTTPGqYVLTGLQSGQPKHLLLVDPEG---VVRTKDHRFESVSHLISYH 559
Cdd:cd10349    1 AWFHGFITRREAERLLepKPQGCYLVRFSESAVT-FVLSYRSRTCCRHFLLAQLRDgrhVVLGEDSAHARLQDLLLHY 77

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 194239662 488 WFHGKLSRREAEALLQL---NGDFLVRESTTTPGQYVLTGLQSGQPKH---------LLLVDPEgvvrtkdhRFESVSHL 555
Cdd:cd10340    2 WFHPVISGIEAENLLKTrgvDGSFLARPSKSNPGDFTLSVRRGDEVTHikiqntgdyYDLYGGE--------KFATLSEL 73

                 ....*...
gi 194239662 556 ISYHMDNH 563
Cdd:cd10340   74 VQYYMEQH 81

Src homology 2 (SH2) domain found in Fyn isoform a like proteins; Fyn is a member of the Src non-receptor type tyrosine kinase family of proteins. This cd contains the SH2 domain found in Fyn isoform a type proteins. Fyn is involved in the control of cell growth and is required in the following pathways: T and B cell receptor signaling, integrin-mediated signaling, growth factor and cytokine receptor signaling, platelet activation, ion channel function, cell adhesion, axon guidance, fertilization, entry into mitosis, and differentiation of natural killer cells, oligodendrocytes and keratinocytes. The protein associates with the p85 subunit of phosphatidylinositol 3-kinase and interacts with the Fyn-binding protein. Alternatively spliced transcript variants encoding distinct isoforms exist. Fyn is primarily localized to the cytoplasmic leaflet of the plasma membrane. Tyrosine phosphorylation of target proteins by Fyn serves to either regulate target protein activity, and/or to generate a binding site on the target protein that recruits other signaling molecules. FYN has been shown to interact with a number of proteins including: BCAR1, Cbl, Janus kinase, nephrin, Sky, tyrosine kinase, Wiskott-Aldrich syndrome protein, and Zap-70. Fyn 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 194239662 484 RGEPWFHGKLSRREAEALLQLNGD----FLVRESTTTPGQYVLT-----GLQSGQPKHLLL--VDPEGVVRTKDHRFESV 552
Cdd:cd10418    1 QAEEWYFGKLGRKDAERQLLSFGNprgtFLIRESETTKGAYSLSirdwdDMKGDHVKHYKIrkLDNGGYYITTRAQFETL 80

                 ....*....
gi 194239662 553 SHLISYHMD 561
Cdd:cd10418   81 QQLVQHYSE 89