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 1907093245 492 EELNAEPWYQGEMSRKEAEALLREDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIRTKDRVFDSISHLINYHL 571
Cdd:cd09925     2 EQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYHV 81

                          90       100
                  ....*....|....*....|...
gi 1907093245 572 ESSLPIVSAGSELCLQQPVERKP 594
Cdd:cd09925    82 TNGLPIISEGSELHLRRPVRRPA 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 1907093245 492 EELNAEPWYQGEMSRKEAEALLREDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIRTKDRVFDSISHLINYHL 571
Cdd:cd09925     2 EQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYHV 81

                          90       100
                  ....*....|....*....|...
gi 1907093245 572 ESSLPIVSAGSELCLQQPVERKP 594
Cdd:cd09925    82 TNGLPIISEGSELHLRRPVRRPA 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 1907093245  150 GPGVTYVVKYLGCIEVLRSMRSldfstrtQVTREAISRVCEAVPGakgalkKRKPPSKMLssilgksnlqfagmsisLTI 229
Cdd:smart00462   1 GSGVSFRVKYLGSVEVPEARGL-------QVVQEAIRKLRAAQGS------EKKEPQKVI-----------------LSI 50

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245  230 STASLNLRTPDSKQIIANHHMRSISFAsGGDPDTTDYVAYVAKDPVNRR-ACHILECCDgLAQDVIGSIGQAFELRFKQY 308
Cdd:smart00462  51 SSRGVKLIDEDTKAVLHEHPLRRISFC-AVGPDDLDVFGYIARDPGSSRfACHVFRCEK-AAEDIALAIGQAFQLAYELK 128

                   ....*
gi 1907093245  309 LQCPS 313
Cdd:smart00462 129 LKARS 133

SH2 domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1907093245 499 WYQGEMSRKEAEALLR---EDGDFLVRKSTTNPGSFVLTGMHNGQAKH--LLLVDPEGTIRTKDRVFDSISHLINYH 570
Cdd:pfam00017   1 WYHGKISRQEAERLLLngkPDGTFLVRESESTPGGYTLSVRDDGKVKHykIQSTDNGGYYISGGVKFSSLAELVEHY 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 1907093245 492 EELNAEPWYQGEMSRKEAEALLREDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIRTKDRVFDSISHLINYHL 571
Cdd:cd09925     2 EQLRGEPWYHGKMSRRDAESLLQTDGDFLVRESTTTPGQYVLTGMQNGQPKHLLLVDPEGVVRTKDRVFESISHLINYHV 81

                          90       100
                  ....*....|....*....|...
gi 1907093245 572 ESSLPIVSAGSELCLQQPVERKP 594
Cdd:cd09925    82 TNGLPIISEGSELHLRRPVRRPA 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 1907093245  150 GPGVTYVVKYLGCIEVLRSMRSldfstrtQVTREAISRVCEAVPGakgalkKRKPPSKMLssilgksnlqfagmsisLTI 229
Cdd:smart00462   1 GSGVSFRVKYLGSVEVPEARGL-------QVVQEAIRKLRAAQGS------EKKEPQKVI-----------------LSI 50

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245  230 STASLNLRTPDSKQIIANHHMRSISFAsGGDPDTTDYVAYVAKDPVNRR-ACHILECCDgLAQDVIGSIGQAFELRFKQY 308
Cdd:smart00462  51 SSRGVKLIDEDTKAVLHEHPLRRISFC-AVGPDDLDVFGYIARDPGSSRfACHVFRCEK-AAEDIALAIGQAFQLAYELK 128

                   ....*
gi 1907093245  309 LQCPS 313
Cdd:smart00462 129 LKARS 133

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 1907093245 492 EELNAEPWYQGEMSRKEAEALLREDGDFLVRKS---TTNPGSFVLTGMHNGQAKHLLL-VDPEGTIRTKDRVFDSISHLI 567
Cdd:cd10361     1 KDLENEPYYHGLLPREDAEELLKNDGDFLVRKTepkGGGKRKLVLSVRWDGKIRHFVInRDDGGKYYIEGKSFKSISELI 80

                          90
                  ....*....|
gi 1907093245 568 NYHLESSLPI 577
Cdd:cd10361    81 NYYQKTKEPI 90

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 1907093245 498 PWYQGEMSRKEAEALLR--EDGDFLVRKSTTNPGSFVLTGMH-NGQAKHLLLVDPEGT---IRTKDRVFDSISHLINYH 570
Cdd:cd00173     1 PWFHGSISREEAERLLRgkPDGTFLVRESSSEPGDYVLSVRSgDGKVKHYLIERNEGGyylLGGSGRTFPSLPELVEHY 79

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 1907093245 153 VTYVVKYLGCIEVLRSMRSldfstrtQVTREAISRVceavpgAKGALKKRKPPSKMLssilgksnlqfagmsisLTISTA 232
Cdd:cd00934     1 ASFQVKYLGSVEVGSSRGV-------DVVEEALKAL------AAALKSSKRKPGPVL-----------------LEVSSK 50

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1907093245 233 SLNLRTPDSKQIIANHHMRSISFaSGGDPDTTDYVAYVAKDP-VNRRACHILECCDG-LAQDVIGSIGQAF 301
Cdd:cd00934    51 GVKLLDLDTKELLLRHPLHRISY-CGRDPDNPNVFAFIAGEEgGSGFRCHVFQCEDEeEAEEILQAIGQAF 120

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245 499 WYQGEMSRKEAEALLRE---DGDFLVRKSTTNPGSFVLTGMHNGQ-AKHLLlvdpegtIRTKDRV--------FDSISHL 566
Cdd:cd09931     2 WFHGHLSGKEAEKLLLEkgkPGSFLVRESQSKPGDFVLSVRTDDDkVTHIM-------IRCQGGKydvgggeeFDSLTDL 74

                          90       100
                  ....*....|....*....|....*..
gi 1907093245 567 INYHLESslPIV-SAGSELCLQQPVER 592
Cdd:cd09931    75 VEHYKKN--PMVeTSGTVVHLKQPLNA 99

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
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1907093245 497 EPWYQGEMSRKEAEALLRE----DGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLV 547
Cdd:cd09944     5 QPWFHGGISRDEAARLIRQqglvDGVFLVRESQSNPGAFVLSLKHGQKIKHYQII 59

N-terminal Src homology 2 (SH2) domain found in SH2 domains, ANK, and kinase domain (shark) proteins; These non-receptor protein-tyrosine kinases contain two SH2 domains, five ankyrin (ANK)-like repeats, and a potential tyrosine phosphorylation site in the carboxyl-terminal tail which resembles the phosphorylation site in members of the src family. Like, mammalian non-receptor protein-tyrosine kinases, ZAP-70 and syk proteins, they do not have SH3 domains. However, the presence of ANK makes these unique among protein-tyrosine kinases. Both tyrosine kinases and ANK repeats have been shown to transduce developmental signals, and SH2 domains are known to participate intimately in tyrosine kinase signaling. These tyrosine kinases are believed to be involved in epithelial cell polarity. The members of this family include the shark (SH2 domains, ANK, and kinase domain) gene in Drosophila and yellow fever mosquitos, as well as the hydra protein HTK16. Drosophila Shark is proposed to transduce intracellularly the Crumbs, a protein necessary for proper organization of ectodermal epithelia, intercellular signal. In general SH2 domains are involved in signal transduction. They typically bind pTyr-containing ligands via two surface pockets, a pTyr and hydrophobic binding pocket, allowing proteins with SH2 domains to localize to tyrosine phosphorylated sites.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1907093245 499 WYQGEMSRKEAEALL----REDGDFLVRKSTTNPGSFVLTGMHNGQAKH 543
Cdd:cd10347     3 WYHGKISREVAEALLlregGRDGLFLVRESTSAPGDYVLSLLAQGEVLH 51

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 1907093245 493 ELNAEPWYQGEMSRKEAEALL--REDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIR-TKDRVFDSISHLINY 569
Cdd:cd10405     1 DLSVHLWYAGPMERAGAESILanRSDGTYLVRQRVKDAAEFAISIKYNVEVKHIKIMTAEGLYRiTEKKAFRGLTELVEF 80

                          90       100
                  ....*....|....*....|
gi 1907093245 570 HLESSLPIVSAGSELCLQQP 589
Cdd:cd10405    81 YQQNSLKDCFKSLDTTLQFP 100

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 1907093245 493 ELNAEPWYQGEMSRKEAEALLR--EDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIR-TKDRVFDSISHLINY 569
Cdd:cd09942     3 SLQEAEWYWGDISREEVNEKMRdtPDGTFLVRDASTMKGDYTLTLRKGGNNKLIKIFHRDGKYGfSDPLTFNSVVELINY 82

                          90       100
                  ....*....|....*....|...
gi 1907093245 570 HLESSLPIVSAGSELCLQQPVER 592
Cdd:cd09942    83 YRNNSLAEYNRKLDVKLLYPVSR 105

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 1907093245 492 EELNAEPWYQGEMSRKEAEALLR---EDGDFLVRKSTTNPGS--FVLTGMHNG-----------QAKHLLLvdpeGTIRT 555
Cdd:cd09929     6 ADLLPKEWYAGNIDRKEAEEALRrsnKDGTFLVRDSSGKDSSqpYTLMVLYNDkvyniqirfleNTRQYAL----GTGLR 81

                          90       100       110
                  ....*....|....*....|....*....|....*....
gi 1907093245 556 KDRVFDSISHLINYHLESSLPIV---SAGSEL-CLQQPV 590
Cdd:cd09929    82 GEETFSSVAEIIEHHQKTPLLLIdgkDNTKDStCLLYAA 120

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 1907093245 499 WYQGEMSRKEAEALLRE---DGDFLVRKSTTnPGSFVLT----GMHNGQAKHLLL-VDPEGTIRTKDR-VFDSISHLINY 569
Cdd:cd09934     8 WYVGDMSRQRAESLLKQedkEGCFVVRNSST-KGLYTVSlftkVPGSPHVKHYHIkQNARSEFYLAEKhCFETIPELINY 86

                  .
gi 1907093245 570 H 570
Cdd:cd09934    87 H 87

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1907093245 495 NAEPWYQGEMSRKEAEALL--REDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIRT-KDRVFDSISHLI 567
Cdd:cd09937     1 SLMPWFHGKISREEAERLLqpPEDGLFLVRESTNYPGDYTLCVSFEGKVEHYRVIYRNGKLTIdEEEYFENLIQLV 76

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245 497 EPWYQGEMSRKEAEALLR--EDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLV---DPEGTIRTKDRVFDSISHLINYHL 571
Cdd:cd09945     1 QGWYHGAITRIEAESLLRpcKEGSYLVRNSESTKQDYSLSLKSAKGFMHMRIQrneTGQYILGQFSRPFETIPEMIRHYC 80

                          90
                  ....*....|....*....
gi 1907093245 572 ESSLPIVSAgSELCLQQPV 590
Cdd:cd09945    81 LNKLPVRGA-EHMCLLEPV 98

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 1907093245 495 NAEPWYQGEMSRKEAEALL----REDGDFLVRKSTTNPGSFVLT-----GMHNGQAKHLllvdpegTIRTKD-------- 557
Cdd:cd09933     1 EAEEWFFGKIKRKDAEKLLlapgNPRGTFLIRESETTPGAYSLSvrdgdDARGDTVKHY-------RIRKLDnggyyitt 73

                          90
                  ....*....|....*...
gi 1907093245 558 -RVFDSISHLINYHLESS 574
Cdd:cd09933    74 rATFPTLQELVQHYSKDA 91

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 1907093245 493 ELNAEPWYQGEMSRKEAEALL-----REDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLL-VDPEGTIRTKDRVFDSISHL 566
Cdd:cd10411     4 ELSDYPWFHGTLSRVKAAQLVlaggpRSHGLFVIRQSETRPGEYVLTFNFQGKAKHLRLsLNGHGQCHVQHLWFQSVFDM 83

                          90
                  ....*....|...
gi 1907093245 567 INYHLESSLPIVS 579
Cdd:cd10411    84 LRHFHTHPIPLES 96

Src homology 2 (SH2) domain found in SH2B adapter proteins (SH2B1, SH2B2, SH2B3); SH2B3 (Lnk), 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. 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 1907093245 494 LNAEPWYQGEMSRKEAEALLREDG-----DFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPE-GTIRTKDRVFDSISHLI 567
Cdd:cd10412     5 LSCYPWFHGPISRVKAAQLVQLQGpdahgVFLVRQSETRRGEYVLTFNFQGRAKHLRLSLTErGQCRVQHLHFPSVVDML 84

                          90
                  ....*....|
gi 1907093245 568 NYHLESSLPI 577
Cdd:cd10412    85 HHFQRSPIPL 94

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 1907093245 498 PWYQGEMSRKEAEALL---REDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLV-DPEGTIRTKDRVFDSISHLINYH 570
Cdd:cd10354     1 IWFHGKISREEAYNMLvkvGGPGSFLVRESDNTPGDYSLSFRVNEGIKHFKIIpTGNNQFMMGGRYFSSLDDVIDRY 77

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 1907093245 499 WYQGEMSRKEAEALLR--EDGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVdpegtiRTKDR---------VFDSISHLI 567
Cdd:cd10392     3 WYHGAISRTDAENLLRlcKEASYLVRNSETSKNDFSLSLKSSQGFMHMKLS------RTKEHkyvlgqnspPFSSVPEII 76

                          90       100
                  ....*....|....*....|...
gi 1907093245 568 NYHLESSLPIVSAgSELCLQQPV 590
Cdd:cd10392    77 HHYASRKLPIKGA-EHMSLLYPV 98

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
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1907093245 496 AEPWYQGEMSRKEAEALLRE----DGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPE 550
Cdd:cd10414     4 SQPWFHHKISRDEAQRLIIQqglvDGVFLVRDSQSNPRTFVLSMSHGQKIKHFQIIPVE 62

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245 499 WYQGEMSRKEAEALL--REDGDFLVRKSTTNPGSFVLTGMHNGQAKH-----LLLVDPEGT-IRTKDRVFDSISHLINYH 570
Cdd:cd09926     9 WYFGPMSRQEAQELLqgQRHGVFLVRDSSTIPGDYVLSVSENSRVSHyiinsLGQPAPNQSrYRIGDQEFDDLPALLEFY 88

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245 498 PWYQGEMSRKEAEALLRE--DGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIR-TKDRVFDSISHLINYHLESS 574
Cdd:cd10406     6 PWFAGNMERQQTDNLLKShaSGTYLIRERPAEAERFAISIKFNDEVKHIKVVEKDNWIHiTEAKKFESLLELVEYYQCHS 85

                  .
gi 1907093245 575 L 575
Cdd:cd10406    86 L 86

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245 498 PWYQGEMSRKEAEALLRE----DGDFLVRKSTTNPGSFVLTGMHNGQAKHLLLV-DPEGTIRTKD-RVFDSISHLINYHL 571
Cdd:cd09938     2 PFFYGSITREEAEEYLKLagmsDGLFLLRQSLRSLGGYVLSVCHGRKFHHYTIErQLNGTYAIAGgKAHCGPAELCEYHS 81

                          90       100
                  ....*....|....*....|....
gi 1907093245 572 ESSlpivsaGSELC-LQQPVERKP 594
Cdd:cd09938    82 TDL------DGLVClLRKPCNRPP 99

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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907093245 494 LNAEP---WYQGEMSRKEAEALLRED---GDFLVRKSTTNPGSFVLTGMHNGQAKHLLLVDPEGTIRTKDRVFDSISHLI 567
Cdd:cd10353    13 LTAPPtnqWYHGRLDRTIAEERLRQAgklGSYLIRESDRRPGSFVLSFLSRTGVNHFRIIAMCGDYYIGGRRFSSLSDLI 92

                  ...
gi 1907093245 568 NYH 570
Cdd:cd10353    93 GYY 95

Src homology 2 domain found in Tensin-like proteins; SH2 domain found in Tensin-like proteins. The Tensins are a family of intracellular proteins that interact with receptor tyrosine kinases (RTKs), integrins, and actin. They are thought act as signaling bridges between the extracellular space and the cytoskeleton. There are four homologues: Tensin1, Tensin2 (TENC1, C1-TEN), Tensin3 and Tensin4 (cten), all of which contain a C-terminal tandem SH2-PTB domain pairing, as well as actin-binding regions that may localize them to focal adhesions. The isoforms of Tensin2 and Tensin3 contain N-terminal C1 domains, which are atypical and not expected to bind to phorbol esters. Tensins 1-3 contain a phosphatase (PTPase) and C2 domain pairing which resembles PTEN (phosphatase and tensin homologue deleted on chromosome 10) protein. PTEN is a lipid phosphatase that dephosphorylates phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P3) to yield phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). As PtdIns(3,4,5)P3 is the product of phosphatidylinositol 3-kinase (PI3K) activity, PTEN is therefore a key negative regulator of the PI3K pathway. Because of their PTEN-like domains, the Tensins may also possess phosphoinositide-binding or phosphatase capabilities. However, only Tensin2 and Tensin3 have the potential to be phosphatases since only their PTPase domains contain a cysteine residue that is essential for catalytic activity. 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 1907093245 499 WYQGEMSRKEAEALLR--EDGDFLVRKSTTNPGSFVL-----------------TGMHNGQAKHLLLVDPEGTIRTK--- 556
Cdd:cd09927     5 WYKPNISRDQAIALLKdkPPGTFLVRDSTTYKGAYGLavkvatpppgvnpfeakGDPESELVRHFLIEPSPKGVKLKgcp 84

                          90       100
                  ....*....|....*....|
gi 1907093245 557 -DRVFDSISHLINYHLESSL 575
Cdd:cd09927    85 nEPVFGSLSALVYQHSITPL 104