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 1958763963 224 KQQLWSEECFHGRLSRGAAERLLVKDGDFLVRESVTSPGQFVLSGLQGGQAKHLLLVDPEGKVRTKDHVFDNVGHLIKYH 303
Cdd:cd09925     1 AEQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYH 80

                          90       100
                  ....*....|....*....|
gi 1958763963 304 MDNSLPIISSGSEVSLKQPV 323
Cdd:cd09925    81 VTNGLPIISEGSELHLRRPV 100

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 1958763963 224 KQQLWSEECFHGRLSRGAAERLLVKDGDFLVRESVTSPGQFVLSGLQGGQAKHLLLVDPEGKVRTKDHVFDNVGHLIKYH 303
Cdd:cd09925     1 AEQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYH 80

                          90       100
                  ....*....|....*....|
gi 1958763963 304 MDNSLPIISSGSEVSLKQPV 323
Cdd:cd09925    81 VTNGLPIISEGSELHLRRPV 100

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 1958763963  230 EECFHGRLSRGAAERLLVK--DGDFLVRESVTSPGQFVLSGLQGGQAKHLLL-VDPEGKVR-TKDHVFDNVGHLIKYHMD 305
Cdd:smart00252   1 QPWYHGFISREEAEKLLKNegDGDFLVRDSESSPGDYVLSVRVKGKVKHYRIrRNEDGKFYlEGGRKFPSLVELVEHYQK 80

                   ....
gi 1958763963  306 NSLP 309
Cdd:smart00252  81 NSLG 84

SH2 domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1958763963 233 FHGRLSRGAAERLLV---KDGDFLVRESVTSPGQFVLSGLQGGQAKH--LLLVDPEGKVRTKDHVFDNVGHLIKYH 303
Cdd:pfam00017   2 YHGKISRQEAERLLLngkPDGTFLVRESESTPGGYTLSVRDDGKVKHykIQSTDNGGYYISGGVKFSSLAELVEHY 77

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 1958763963 224 KQQLWSEECFHGRLSRGAAERLLVKDGDFLVRESVTSPGQFVLSGLQGGQAKHLLLVDPEGKVRTKDHVFDNVGHLIKYH 303
Cdd:cd09925     1 AEQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYH 80

                          90       100
                  ....*....|....*....|
gi 1958763963 304 MDNSLPIISSGSEVSLKQPV 323
Cdd:cd09925    81 VTNGLPIISEGSELHLRRPV 100

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 1958763963  230 EECFHGRLSRGAAERLLVK--DGDFLVRESVTSPGQFVLSGLQGGQAKHLLL-VDPEGKVR-TKDHVFDNVGHLIKYHMD 305
Cdd:smart00252   1 QPWYHGFISREEAEKLLKNegDGDFLVRDSESSPGDYVLSVRVKGKVKHYRIrRNEDGKFYlEGGRKFPSLVELVEHYQK 80

                   ....
gi 1958763963  306 NSLP 309
Cdd:smart00252  81 NSLG 84

Phosphotyrosine interaction domain (PTB/PID);

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1958763963   1 MQSISFASGGDPDTTDYVAYVAKD-PVNQRACHILECRSGtAQDIISTIGQAFELR 55
Cdd:pfam00640  79 LVSISFCADGDPDLMRYFAYIARDkATNKFACHVFESEDG-AQDIAQSIGQAFALA 133

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 1958763963 233 FHGRLSRGAAERLLVKDGDFLVRESVTSPGQFVLSGLQGGQAKH-----LLLVDPEGKVRT----KDHVFDNVGHLIKYH 303
Cdd:cd10337     9 YHGRIPRQVAESLVQREGDFLVRDSLSSPGDYVLTCRWKGQPLHfkinrVVLRPSEAYTRVqyqfEDEQFDSIPALVHFY 88

                          90       100
                  ....*....|....*....|...
gi 1958763963 304 MDNSLPiISSGSEVSLKQPVKKH 326
Cdd:cd10337    89 VGNRRP-ISQASGAIISRPVNRT 110

Src homology 2 (SH2) domain; In general, SH2 domains are involved in signal transduction; they bind pTyr-containing polypeptide ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites. They are present in a wide array of proteins including: adaptor proteins (Nck1, Crk, Grb2), scaffolds (Slp76, Shc, Dapp1), kinases (Src, Syk, Fps, Tec), phosphatases (Shp-1, Shp-2), transcription factors (STAT1), Ras signaling molecules (Ras-Gap), ubiquitination factors (c-Cbl), cytoskeleton regulators (Tensin), signal regulators (SAP), and phospholipid second messengers (PLCgamma), amongst others.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1958763963 231 ECFHGRLSRGAAERLL--VKDGDFLVRESVTSPGQFVLSGLQG-GQAKHLLLVDPEGK---VRTKDHVFDNVGHLIKYH 303
Cdd:cd00173     1 PWFHGSISREEAERLLrgKPDGTFLVRESSSEPGDYVLSVRSGdGKVKHYLIERNEGGyylLGGSGRTFPSLPELVEHY 79

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
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1958763963    1 MQSISFASGgDPDTTDYVAYVAKDPVNQR-ACHILECRSGtAQDIISTIGQAFELRFKQYLKNPSL 65
Cdd:smart00462  71 LRRISFCAV-GPDDLDVFGYIARDPGSSRfACHVFRCEKA-AEDIALAIGQAFQLAYELKLKARSE 134

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 1958763963 229 SEECFHGRLSRG--AAERLLVK-----DGDFLVRESVTSPGQFVLSGLQGGQAKH----LLLVDPEGKVRTKDH-VFDNV 296
Cdd:cd10341     3 TEPWFHGKLGDGrdEAEKLLLEyceggDGTFLVRESETFVGDYTLSFWRNGKVQHcrirSRQENGEKKYYLTDNlVFDSL 82

                          90
                  ....*....|..
gi 1958763963 297 GHLIKYHMDNSL 308
Cdd:cd10341    83 YELIDYYRQNPL 94

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 1958763963 233 FHGRLSRGAAERLLVK---DGDFLVRESVTSPGQFVLSGLQGGQAKHL-LLVDPEGKVRTKDHVFDNVGHLIKYHMDNSl 308
Cdd:cd09941     6 FHGKISRAEAEEILMNqrpDGAFLIRESESSPGDFSLSVKFGNDVQHFkVLRDGAGKYFLWVVKFNSLNELVDYHRTTS- 84

                          90
                  ....*....|.
gi 1958763963 309 piISSGSEVSL 319
Cdd:cd09941    85 --VSRNQQIFL 93

C-terminal Src homology 2 (C-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 1958763963 229 SEECFHGRLSRGAAERLLVK---DGDFLVRESVTSPGQFVLSGLQGGQAKHLLLvDPEGKVRT-KDHVFDNVGHLIKYHM 304
Cdd:cd09932     3 SKEWFHANLTREQAEEMLMRvprDGAFLVRPSETDPNSFAISFRAEGKIKHCRI-KQEGRLFViGTSQFESLVELVSYYE 81

                          90
                  ....*....|....*....
gi 1958763963 305 DNSLPiissgSEVSLKQPV 323
Cdd:cd09932    82 KHPLY-----RKIKLRYPV 95

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 1958763963 229 SEECFHGRLSRGAAERLLV----KDGDFLVRESVTSPGQFVLS-----GLQGGQAKHLllvdpegKVRTKDH-------- 291
Cdd:cd09933     2 AEEWFFGKIKRKDAEKLLLapgnPRGTFLIRESETTPGAYSLSvrdgdDARGDTVKHY-------RIRKLDNggyyittr 74

                          90
                  ....*....|....*..
gi 1958763963 292 -VFDNVGHLIKYHMDNS 307
Cdd:cd09933    75 aTFPTLQELVQHYSKDA 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 1958763963 233 FHGRLSRGAAERLLVK---DGDFLVRESVTSPGQFVLSGLQGGQAKHLLLV-DPEGKVRTKDHVFDNVGHLIKYH 303
Cdd:cd10354     3 FHGKISREEAYNMLVKvggPGSFLVRESDNTPGDYSLSFRVNEGIKHFKIIpTGNNQFMMGGRYFSSLDDVIDRY 77

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 1958763963 226 QLWseecFHGRLSRGAAERLLV--KDGDFLVRESVTSPGQFVLSGLQGGQAKHLLLV-DPEGKVR-TKDHVFDNVGHLIK 301
Cdd:cd09940     5 FLW----FVGEMERDTAENRLEnrPDGTYLVRVRPQGETQYALSIKYNGDVKHMKIEqRSDGLYYlSESRHFKSLVELVN 80

                          90       100
                  ....*....|....*....|..
gi 1958763963 302 YHMDNSLPIISSGSEVSLKQPV 323
Cdd:cd09940    81 YYERNSLGENFAGLDTTLKWPY 102

Src homology 2 domain found in SH2 domain-containing adapter protein F (SHF); SHF is thought to play a role in PDGF-receptor signaling and regulation of apoptosis. SHF is mainly expressed in skeletal muscle, brain, liver, prostate, testis, ovary, small intestine, and colon. SHF contains four putative tyrosine phosphorylation sites and an SH2 domain. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763963 226 QLWseecFHGRLSRGAAERL--LVKDGDFLVRESVTSPGQFVLSgLQGGQA-KHLLLvdpegkVRTKDH---------VF 293
Cdd:cd10392     1 QVW----YHGAISRTDAENLlrLCKEASYLVRNSETSKNDFSLS-LKSSQGfMHMKL------SRTKEHkyvlgqnspPF 69

                          90       100       110
                  ....*....|....*....|....*....|.
gi 1958763963 294 DNVGHLIKYHMDNSLPIisSGSE-VSLKQPV 323
Cdd:cd10392    70 SSVPEIIHHYASRKLPI--KGAEhMSLLYPV 98

Src homology 2 (SH2) domain found in Tec-like proteins; The Tec protein tyrosine kinase is the founding member of a family that includes Btk, Itk, Bmx, and Txk. The members have a PH domain, a zinc-binding motif, a SH3 domain, a SH2 domain, and a protein kinase catalytic domain. Btk is involved in B-cell receptor signaling with mutations in Btk responsible for X-linked agammaglobulinemia (XLA) in humans and X-linked immunodeficiency (xid) in mice. Itk is involved in T-cell receptor signaling. Tec is expressed in both T and B cells, and is thought to function in activated and effector T lymphocytes to induce the expression of genes regulated by NFAT transcription factors. 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 1958763963 231 ECFHGRLSRGAAERLLV---KDGDFLVRESVTsPGQFVLS----GLQGGQAKHLLL-VDPEGKVR-TKDHVFDNVGHLIK 301
Cdd:cd09934     7 EWYVGDMSRQRAESLLKqedKEGCFVVRNSST-KGLYTVSlftkVPGSPHVKHYHIkQNARSEFYlAEKHCFETIPELIN 85

                          90       100
                  ....*....|....*....|..
gi 1958763963 302 YHMDNSLPIISsgsevSLKQPV 323
Cdd:cd09934    86 YHQHNSGGLAT-----RLKYPV 102

Src homology 2 (SH2) domain found in the Nck family; 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 1958763963 233 FHGRLSRGAAERLLVK---DGDFLVRESVTSPGQFVLSGLQGGQAKHLLLVDPEGKVRTKDHVFDNVGHLIKYHMdnSLP 309
Cdd:cd09943     4 YYGRITRHQAETLLNEhghEGDFLIRDSESNPGDYSVSLKAPGRNKHFKVQVVDNVYCIGQRKFHTMDELVEHYK--KAP 81

                  ....
gi 1958763963 310 IISS 313
Cdd:cd09943    82 IFTS 85

Src homology 2 (SH2) domain found in SH2B adapter proteins (SH2B1, SH2B2, SH2B3); SH2B2 (APS), like other members of the SH2B adapter protein family, contains 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. 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 1958763963 233 FHGRLSRGAAERLLVKDGD-----FLVRESVTSPGQFVLSGLQGGQAKHLLL-VDPEGKVRTKDHVFDNVGHLIKYHMDN 306
Cdd:cd10411    11 FHGTLSRVKAAQLVLAGGPrshglFVIRQSETRPGEYVLTFNFQGKAKHLRLsLNGHGQCHVQHLWFQSVFDMLRHFHTH 90

                  ....*.
gi 1958763963 307 SLPIIS 312
Cdd:cd10411    91 PIPLES 96

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763963 227 LWseecFHGRLSRGAAERLLVK--DGDFLVRESVTSPGQFVLSGLQGGQAKHLLLVDPEGKVR-TKDHVFDNVGHLIKYH 303
Cdd:cd10405     6 LW----YAGPMERAGAESILANrsDGTYLVRQRVKDAAEFAISIKYNVEVKHIKIMTAEGLYRiTEKKAFRGLTELVEFY 81

                          90       100
                  ....*....|....*....|..
gi 1958763963 304 MDNSLPIISSGSEVSLKQPVKK 325
Cdd:cd10405    82 QQNSLKDCFKSLDTTLQFPFKE 103

Src homology 2 (SH2) domain found in Gardner-Rasheed feline sarcoma viral (v-fgr) oncogene homolog, Fgr; Fgr is a member of the Src non-receptor type tyrosine kinase family of proteins. The protein contains N-terminal sites for myristoylation and palmitoylation, a PTK domain, and SH2 and SH3 domains which are involved in mediating protein-protein interactions with phosphotyrosine-containing and proline-rich motifs, respectively. Fgr is expressed in B-cells and myeloid cells, localizes to plasma membrane ruffles, and functions as a negative regulator of cell migration and adhesion triggered by the beta-2 integrin signal transduction pathway. Multiple alternatively spliced variants, encoding the same protein, have been identified Fgr has been shown to interact with Wiskott-Aldrich syndrome protein. Fgr 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 1958763963 229 SEECFHGRLSRGAAERLLVKDGD----FLVRESVTSPGQFVLS-----GLQGGQAKHLLL--VDPEGKVRTKDHVFDNVG 297
Cdd:cd10367     2 AEEWYFGKIGRKDAERQLLSPGNprgaFLIRESETTKGAYSLSirdwdQNRGDHVKHYKIrkLDTGGYYITTRAQFDTVQ 81

                  ....*...
gi 1958763963 298 HLIKYHMD 305
Cdd:cd10367    82 ELVQHYME 89

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 1958763963 233 FHGRLSRGAAERLLV---KDGDFLVRESVTSPGQFVLSGLQGGQAKH---------LLLVDPEGkvrtkdhvFDNVGHLI 300
Cdd:cd10340     3 FHPVISGIEAENLLKtrgVDGSFLARPSKSNPGDFTLSVRRGDEVTHikiqntgdyYDLYGGEK--------FATLSELV 74

                          90       100
                  ....*....|....*....|....
gi 1958763963 301 KYHMDNSLPIIS-SGSEVSLKQPV 323
Cdd:cd10340    75 QYYMEQHGQLREkNGDVIELKYPL 98

Src homology 2 (SH2) domain in lymphocyte cell kinase (Lck); Lck is a member of the Src non-receptor type tyrosine kinase family of proteins. It is expressed in the brain, T-cells, and NK cells. The unique domain of Lck mediates its interaction with two T-cell surface molecules, CD4 and CD8. It associates with their cytoplasmic tails on CD4 T helper cells and CD8 cytotoxic T cells to assist signaling from the T cell receptor (TCR) complex. When the T cell receptor is engaged by the specific antigen presented by MHC, Lck phosphorylase the intracellular chains of the CD3 and zeta-chains of the TCR complex, allowing ZAP-70 to bind them. Lck then phosphorylates and activates ZAP-70, which in turn phosphorylates Linker of Activated T cells (LAT), a transmembrane protein that serves as a docking site for proteins including: Shc-Grb2-SOS, PI3K, and phospholipase C (PLC). The tyrosine phosphorylation cascade culminates in the intracellular mobilization of a calcium ions and activation of important signaling cascades within the lymphocyte, including the Ras-MEK-ERK pathway, which goes on to activate certain transcription factors such as NFAT, NF-kappaB, and AP-1. These transcription factors regulate the production cytokines such as Interleukin-2 that promote long-term proliferation and differentiation of the activated lymphocytes. The N-terminal tail of Lck is myristoylated and palmitoylated and it tethers the protein to the plasma membrane of the cell. Lck also contains a SH3 domain, a SH2 domain, and a C-terminal tyrosine kinase domain. Lck has 2 phosphorylation sites, the first an autophosphorylation site that is linked to activation of the protein and the second which is phosphorylated by Csk, which inhibits it. Lck is also inhibited by SHP-1 dephosphorylation and by Cbl ubiquitin ligase, which is part of the ubiquitin-mediated pathway. 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 1958763963 229 SEECFHGRLSRGAAERLLVKDGD----FLVRESVTSPGQFVLSglqggqakhlllvdpegkVRTKDHvfdNVGHLIKYH- 303
Cdd:cd10362     2 PEPWFFKNLSRNDAERQLLAPGNthgsFLIRESETTAGSFSLS------------------VRDFDQ---NQGEVVKHYk 60

                          90       100
                  ....*....|....*....|....*....
gi 1958763963 304 ---MDNSLPIISSG-SEVSLKQPVKKHNN 328
Cdd:cd10362    61 irnLDNGGFYISPRiTFPGLHELVRHYTN 89

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 1958763963 229 SEECFHGRLSRGAAERLLV----KDGDFLVRESVTSPGQFVLSGLQGGQAKHLllvdpegkvrtkdhvfdNVGHLIKYHM 304
Cdd:cd10365     2 AEEWYFGKITRRESERLLLnaenPRGTFLVRESETTKGAYCLSVSDFDNAKGL-----------------NVKHYKIRKL 64

                          90       100       110
                  ....*....|....*....|....*....|....
gi 1958763963 305 DNSLPIISSGSE-VSLKQPV---KKHNNpGLSHS 334
Cdd:cd10365    65 DSGGFYITSRTQfNSLQQLVayySKHAD-GLCHR 97

Src homology 2 (SH2) domain found in SH2-containing inositol-5'-phosphatase (SHIP) and SLAM-associated protein (SAP); The SH2-containing inositol-5'-phosphatase, SHIP (also called SHIP1/SHIP1a), is a hematopoietic-restricted phosphatidylinositide phosphatase that translocates to the plasma membrane after extracellular stimulation and hydrolyzes the phosphatidylinositol-3-kinase (PI3K)-generated second messenger PI-3,4,5-P3 (PIP3) to PI-3,4-P2. As a result, SHIP dampens down PIP3 mediated signaling and represses the proliferation, differentiation, survival, activation, and migration of hematopoietic cells. PIP3 recruits lipid-binding pleckstrin homology(PH) domain-containing proteins to the inner wall of the plasma membrane and activates them. PH domain-containing downstream effectors include the survival/proliferation enhancing serine/threonine kinase, Akt (protein kinase B), the tyrosine kinase, Btk, the regulator of protein translation, S6K, and the Rac and cdc42 guanine nucleotide exchange factor, Vav. SHIP is believed to act as a tumor suppressor during leukemogenesis and lymphomagenesis, and may play a role in activating the immune system to combat cancer. SHIP contains an N-terminal SH2 domain, a centrally located phosphatase domain that specifically hydrolyzes the 5'-phosphate from PIP3, PI-4,5-P2 and inositol-1,3,4,5- tetrakisphosphate (IP4), a C2 domain, that is an allosteric activating site when bound by SHIP's enzymatic product, PI-3,4-P2; 2 NPXY motifs that bind proteins with a phosphotyrosine binding (Shc, Dok 1, Dok 2) or an SH2 (p85a, SHIP2) domain; and a proline-rich domain consisting of four PxxP motifs that bind a subset of SH3-containing proteins including Grb2, Src, Lyn, Hck, Abl, PLCg1, and PIAS1. The SH2 domain of SHIP binds to the tyrosine phosphorylated forms of Shc, SHP-2, Doks, Gabs, CD150, platelet-endothelial cell adhesion molecule, Cas, c-Cbl, immunoreceptor tyrosine-based inhibitory motifs (ITIMs), and immunoreceptor tyrosine-based activation motifs (ITAMs). The X-linked lymphoproliferative syndrome (XLP) gene encodes SAP (also called SH2D1A/DSHP) a protein that consists of a 5 residue N-terminus, a single SH2 domain, and a short 25 residue C-terminal tail. XLP is characterized by an extreme sensitivity to Epstein-Barr virus. Both T and natural killer (NK) cell dysfunctions have been seen in XLP patients. SAP binds the cytoplasmic tail of Signaling lymphocytic activation molecule (SLAM), 2B4, Ly-9, and CD84. SAP is believed to function as a signaling inhibitor, by blocking or regulating binding of other signaling proteins. SAP and the SAP-like protein EAT-2 recognize the sequence motif TIpYXX(V/I), which is found in the cytoplasmic domains of a restricted number of T, B, and NK cell surface receptors and are proposed to be natural inhibitors or regulators of the physiological role of a small family of receptors on the surface of these cells. 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 1958763963 226 QLWseecFHGRLSRGAAERLLV---KDGDFLVRESVTSPGQFVLSGL-QGGQAKHLLLVDPEGK--VRTKDHV----FDN 295
Cdd:cd10343     3 PPW----YHGNITRSKAEELLSkagKDGSFLVRDSESVSGAYALCVLyQNCVHTYRILPNAEDKlsVQASEGVpvrfFTT 78

                          90       100       110
                  ....*....|....*....|....*....|
gi 1958763963 296 VGHLIKYHMDNSLPIISsgsevSLKQPVKK 325
Cdd:cd10343    79 LPELIEFYQKENMGLVT-----HLLYPVER 103

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 1958763963 229 SEECFHGRLSRGAAERLLVKDGD----FLVRESVTSPGQFVLS-----GLQGGQAKHLLL--VDPEGKVRTKDHVFDNVG 297
Cdd:cd10418     2 AEEWYFGKLGRKDAERQLLSFGNprgtFLIRESETTKGAYSLSirdwdDMKGDHVKHYKIrkLDNGGYYITTRAQFETLQ 81

                          90
                  ....*....|
gi 1958763963 298 HLIKYHMDNS 307
Cdd:cd10418    82 QLVQHYSERA 91

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
                  ....*....|....*....|....*....|....*....|....*...
gi 1958763963 233 FHGRLSRGAAERLLVK----DGDFLVRESVTSPGQFVLSGLQGGQAKH 276
Cdd:cd09938     4 FYGSITREEAEEYLKLagmsDGLFLLRQSLRSLGGYVLSVCHGRKFHH 51

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958763963 224 KQQLWSEECFHGRLSRGAAE---RLLVKDGDFLVRESVTSPGQ--FVLSGL-----------QGGQAKHLLLvdpeGKVR 287
Cdd:cd09929     5 EADLLPKEWYAGNIDRKEAEealRRSNKDGTFLVRDSSGKDSSqpYTLMVLyndkvyniqirFLENTRQYAL----GTGL 80

                          90       100
                  ....*....|....*....|....*.
gi 1958763963 288 TKDHVFDNVGHLIKYHMDNSLPIISS 313
Cdd:cd09929    81 RGEETFSSVAEIIEHHQKTPLLLIDG 106

N-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 the 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 N-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 1958763963 231 ECFHGRLSRGAAERLLV---KDGDFLVRESVTSPGQFVLSGLQGGQAKHLLLVDPEGKVRTKDHVFDNVGHLIKYH 303
Cdd:cd10353    20 QWYHGRLDRTIAEERLRqagKLGSYLIRESDRRPGSFVLSFLSRTGVNHFRIIAMCGDYYIGGRRFSSLSDLIGYY 95

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.

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gi 1958763963 231 ECFHGRLSRGAAERLLVK---DGDFLVRESVTSPGQFVLSGLQGGQAKHLllvdpegKVRTKDHVF 293
Cdd:cd10408     2 PWYYGKVTRHQAEMALNErgnEGDFLIRDSESSPNDFSVSLKAQGKNKHF-------KVQLKECVY 60

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.

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gi 1958763963   1 MQSISFaSGGDPDTTDYVAYVAKDPVNQRA-CHILECRSGtAQDIISTIGQAFE 53
Cdd:cd13161    65 IKDISF-VTVDPKDKKLFAFISHDPRLGRItCHVFRCKRG-AQEICDTIAEAFK 116

C-terminal Src homology 2 (SH2) domain found in Zeta-chain-associated protein kinase 70 (ZAP-70); 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 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.

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gi 1958763963 233 FHGRLSRGAAERLLVK----DGDFLVRESVTSpGQFVLSGLQGGQAKH-LLLVDPEGKVRTKDHV-FDNVGHLIKY 302
Cdd:cd10402    13 YHGSIARDEAERRLYSgaqpDGKFLLRERKES-GTYALSLVYGKTVYHyRIDQDKSGKYSIPEGTkFDTLWQLVEY 87

Src homology 2 (SH2) domain found in Fyn; Fyn is a member of the Src non-receptor type tyrosine kinase family of 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.

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gi 1958763963 229 SEECFHGRLSRGAAERLLVKDGD----FLVRESVTSPGQFVLS-----GLQGGQAKHLLL--VDPEGKVRTKDHVFDNVG 297
Cdd:cd10368     2 AEEWYFGKLGRKDAERQLLSFGNprgtFLIRESETTKGAYSLSirdwdDMKGDHVKHYKIrkLDNGGYYITTRAQFETLQ 81

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gi 1958763963 298 HLIKYH 303
Cdd:cd10368    82 QLVQHY 87