Src Homology 3 domain superfamily; Src Homology 3 (SH3) domains are protein interaction domains that bind proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. Thus, they are referred to as proline-recognition domains (PRDs). SH3 domains are less selective and show more diverse specificity compared to other PRDs. They have been shown to bind peptide sequences that lack the PxxP motif; examples include the PxxDY motif of Eps8 and the RKxxYxxY sequence in SKAP55. SH3 domain containing proteins play versatile and diverse roles in the cell, including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies, among others. Many members of this superfamily are adaptor proteins that associate with a number of protein partners, facilitating complex formation and signal transduction.

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gi 2217290478  74 QLCALYAFTYTGADGQQVSLAEGDRFLLLRKTNSDWWLARRLEAPSTSRPIFVPAAY 130
Cdd:cd12143     1 QLCALYAYQYTGADGRQVSIAEGERFLLLRKTNSDWWQVRRLEAPSTSRPLFVPATY 57

Src Homology 3 domain of Rho GTPase-activating protein 9 and similar proteins; Rho GTPase-activating proteins (RhoGAPs or ARHGAPs) bind to Rho proteins and enhance the hydrolysis rates of bound GTP. ARHGAP9 functions as a GAP for Rac and Cdc42, but not for RhoA. It negatively regulates cell migration and adhesion. It also acts as a docking protein for the MAP kinases Erk2 and p38alpha, and may facilitate cross-talk between the Rho GTPase and MAPK pathways to control actin remodeling. It contains SH3, WW, Pleckstin homology (PH), and RhoGAP domains. SH3 domains bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs; they play a role in the regulation of enzymes by intramolecular interactions, changing the subcellular localization of signal pathway components and mediate multiprotein complex assemblies.

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gi 2217290478  74 QLCALYAFTYTGADGQQVSLAEGDRFLLLRKTNSDWWLARRLEAPSTSRPIFVPAAY 130
Cdd:cd12143     1 QLCALYAYQYTGADGRQVSIAEGERFLLLRKTNSDWWQVRRLEAPSTSRPLFVPATY 57

Variant SH3 domain;

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gi 2217290478  77 ALYAFTYTGADgqQVSLAEGDRFLLLRKTNSDWWLARRleapsTSRPIFVPAAY 130
Cdd:pfam14604   1 ALYPYEPKDDD--ELSLQRGDVITVIEESEDGWWEGIN-----TGRTGLVPANY 47

Src Homology 3 domain of Rho GTPase-activating protein 9 and similar proteins; Rho GTPase-activating proteins (RhoGAPs or ARHGAPs) bind to Rho proteins and enhance the hydrolysis rates of bound GTP. ARHGAP9 functions as a GAP for Rac and Cdc42, but not for RhoA. It negatively regulates cell migration and adhesion. It also acts as a docking protein for the MAP kinases Erk2 and p38alpha, and may facilitate cross-talk between the Rho GTPase and MAPK pathways to control actin remodeling. It contains SH3, WW, Pleckstin homology (PH), and RhoGAP domains. SH3 domains bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs; they play a role in the regulation of enzymes by intramolecular interactions, changing the subcellular localization of signal pathway components and mediate multiprotein complex assemblies.

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gi 2217290478  74 QLCALYAFTYTGADGQQVSLAEGDRFLLLRKTNSDWWLARRLEAPSTSRPIFVPAAY 130
Cdd:cd12143     1 QLCALYAYQYTGADGRQVSIAEGERFLLLRKTNSDWWQVRRLEAPSTSRPLFVPATY 57

Beta-spectrin pleckstrin homology (PH) domain; ARHGAP family genes encode Rho/Rac/Cdc42-like GTPase activating proteins with RhoGAP domain. The ARHGAP members here all have a PH domain upstream of their C-terminal RhoGAP domain. Some have additional N-terminal SH3 and WW domains. The members here include: ARHGAP9, ARHGAP12, ARHGAP15, and ARHGAP27. ARHGAP27 and ARHGAP12 shared the common-domain structure, consisting of SH3, WW, PH, and RhoGAP domains. The PH domain of ArhGAP9 employs a non-canonical phosphoinositide binding mechanism, a variation of the spectrin- Ins(4,5)P2-binding mode, that gives rise to a unique PI binding profile, namely a preference for both PI(4,5)P2 and the PI 3-kinase products PI(3,4,5)P3 and PI(3,4)P2. This lipid binding mechanism is also employed by the PH domain of Tiam1 and Slm1. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

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gi 2217290478 372 EKSGLLNMTKIAQGGRKLRKNWGPSWVVLTGNSLVFYREPPPTAPSSG 419
Cdd:cd13233     1 EKQGLLNKTKIAENGKKLRKNWSTSWVVLTSSHLLFYKDAKSAAKSGN 48

Src Homology 3 domain of Rho GTPase-activating protein 12; Rho GTPase-activating proteins (RhoGAPs or ARHGAPs) bind to Rho proteins and enhance the hydrolysis rates of bound GTP. ARHGAP12 has been shown to display GAP activity towards Rac1. It plays a role in regulating hepatocyte growth factor (HGF)-driven cell growth and invasiveness. It contains SH3, WW, Pleckstin homology (PH), and RhoGAP domains. SH3 domains bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs; they play a role in the regulation of enzymes by intramolecular interactions, changing the subcellular localization of signal pathway components and mediate multiprotein complex assemblies.

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gi 2217290478  79 YAFTYTGADgQQVSLAEGDRFLLLRKTNSDWWLARRLEApstSRPIFVPAAYMIE 133
Cdd:cd12070     7 YDYDYEAKD-RKIVIKQGERYILVKKTNDDWWQVKKDEN---SKPFYVPAQYVKE 57

Src homology 3 domain of Src kinase-like Protein Tyrosine Kinases; Src subfamily members include Src, Lck, Hck, Blk, Lyn, Fgr, Fyn, Yrk, Yes, and Brk. Src (or c-Src) proteins are cytoplasmic (or non-receptor) PTKs which are anchored to the plasma membrane. They contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). However, Brk lacks the N-terminal myristoylation sites. Src proteins are involved in signaling pathways that regulate cytokine and growth factor responses, cytoskeleton dynamics, cell proliferation, survival, and differentiation. They were identified as the first proto-oncogene products, and they regulate cell adhesion, invasion, and motility in cancer cells, and tumor vasculature, contributing to cancer progression and metastasis. Src kinases are overexpressed in a variety of human cancers, making them attractive targets for therapy. They are also implicated in acute inflammatory responses and osteoclast function. Src, Fyn, Yes, and Yrk are widely expressed, while Blk, Lck, Hck, Fgr, Lyn, and Brk show a limited expression pattern. This subfamily also includes Drosophila Src42A, Src oncogene at 42A (also known as Dsrc41) which accumulates at sites of cell-cell or cell-matrix adhesion, and participates in Drosphila development and wound healing. It has been shown to promote tube elongation in the tracheal system, is essential for proper cell-cell matching during dorsal closure, and regulates cell-cell contacts in developing Drosophila eyes. The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2217290478  77 ALYafTYTGADGQQVSLAEGDRFLLLRKTNSDWWLARRLeapSTSRPIFVPAAY 130
Cdd:cd11845     4 ALY--DYEARTDDDLSFKKGDRLQILDDSDGDWWLARHL---STGKEGYIPSNY 52

Src homology 3 domain of SH3 protein interacting with Nck, 90 kDa (SPIN90); SPIN90 is also called NCK interacting protein with SH3 domain (NCKIPSD), Dia-interacting protein (DIP), 54 kDa vimentin-interacting protein (VIP54), or WASP-interacting SH3-domain protein (WISH). It is an F-actin binding protein that regulates actin polymerization and endocytosis. It associates with the Arp2/3 complex near actin filaments and determines filament localization at the leading edge of lamellipodia. SPIN90 is expressed in the early stages of neuronal differentiation and plays a role in regulating growth cone dynamics and neurite outgrowth. It also interacts with IRSp53 and regulates cell motility by playing a role in the formation of membrane protrusions. SPIN90 contains an N-terminal SH3 domain, a proline-rich domain, and a C-terminal VCA (verprolin-homology and cofilin-like acidic) domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2217290478  77 ALYAFTytGADGQQVSLAEGDRFLLLRKTNSDWWLARRLeapsTSRPIFVPAAY 130
Cdd:cd11849     4 ALYDFK--SAEPNTLSFSEGETFLLLERSNAHWWLVTNH----SGETGYVPANY 51

Src homology 3 domain of Slit-Robo GTPase Activating Protein 4; srGAP4, also called ARHGAP4, is highly expressed in hematopoietic cells and may play a role in lymphocyte differentiation. It is able to stimulate the GTPase activity of Rac1, Cdc42, and RhoA. In the nervous system, srGAP4 has been detected in differentiating neurites and may be involved in axon and dendritic growth. srGAPs are Rho GAPs that interact with Robo1, the transmembrane receptor of Slit proteins. Slit proteins are secreted proteins that control axon guidance and the migration of neurons and leukocytes. srGAPs contain an N-terminal F-BAR domain, a Rho GAP domain, and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2217290478  77 ALYAFTYTGADGQQVSLAEGDRFLLLRKTNSDWW 110
Cdd:cd11956     4 AVACFDYTGRTAQELSFKRGDVLLLHSKASSDWW 37

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

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gi 2217290478   77 ALYAftYTGADGQQVSLAEGDRFLLLRKTNSDWWLARRL 115
Cdd:smart00326   7 ALYD--YTAQDPDELSFKKGDIITVLEKSDDGWWKGRLG 43

Src homology 3 domain of Type I fungal Myosins; Type I myosins (myosin-I) are actin-dependent motors in endocytic actin structures and actin patches. They play roles in membrane traffic in endocytic and secretory pathways, cell motility, and mechanosensing. Saccharomyces cerevisiae has two myosins-I, Myo3 and Myo5, which are involved in endocytosis and the polarization of the actin cytoskeleton. Myosin-I contains an N-terminal actin-activated ATPase, a phospholipid-binding TH1 (tail homology 1) domain, and a C-terminal extension which includes an F-actin-binding TH2 domain, an SH3 domain, and an acidic peptide that participates in activating the Arp2/3complex. The SH3 domain of myosin-I is required for myosin-I-induced actin polymerization. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2217290478  77 ALYAFTYTGADgqQVSLAEGDRFLLLRKTNSDWWLARRLEapsTSRPIFVPAAYMIE 133
Cdd:cd11858     4 ALYDFAGSVAN--ELSLKKDDIVYIVQKEDNGWWLAKKLD---ESKEGWVPAAYLEE 55

Src homology 3 domain of Yes Protein Tyrosine Kinase; Yes (or c-Yes) is a member of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) PTKs. c-Yes kinase is the cellular homolog of the oncogenic protein (v-Yes) encoded by the Yamaguchi 73 and Esh sarcoma viruses. It displays functional overlap with other Src subfamily members, particularly Src. It also shows some unique functions such as binding to occludins, transmembrane proteins that regulate extracellular interactions in tight junctions. Yes also associates with a number of proteins in different cell types that Src does not interact with, like JAK2 and gp130 in pre-adipocytes, and Pyk2 in treated pulmonary vein endothelial cells. Although the biological function of Yes remains unclear, it appears to have a role in regulating cell-cell interactions and vesicle trafficking in polarized cells. Src kinases contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2217290478  77 ALYafTYTGADGQQVSLAEGDRFLLLRKTNSDWWLARRLeapSTSRPIFVPAAYMI 132
Cdd:cd12007     5 ALY--DYEARTTEDLSFKKGERFQIINNTEGDWWEARSI---ATGKNGYIPSNYVA 55

Src homology 3 domain of Blk Protein Tyrosine Kinase; Blk is a member of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) PTKs. It is expressed specifically in B-cells and is involved in pre-BCR (B-cell receptor) signaling. Src kinases contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2217290478  77 ALYAFTYTGADGQQvsLAEGDRFLLLrKTNSDWWLARRLEapsTSRPIFVPAAYM 131
Cdd:cd12009     4 AQYDFVPSNERDLQ--LKKGEKLQVL-KSDGEWWLAKSLT---TGKEGYIPSNYV 52

Src homology 3 domain of Slit-Robo GTPase Activating Proteins; Slit-Robo GTPase Activating Proteins (srGAPs) are Rho GAPs that interact with Robo1, the transmembrane receptor of Slit proteins. Slit proteins are secreted proteins that control axon guidance and the migration of neurons and leukocytes. Vertebrates contain three isoforms of srGAPs (srGAP1-3), all of which are expressed during embryonic and early development in the nervous system but with different localization and timing. A fourth member has also been reported (srGAP4, also called ARHGAP4). srGAPs contain an N-terminal F-BAR domain, a Rho GAP domain, and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2217290478  77 ALYAFTYTGADGQQVSLAEGDRFLLLRKTNSDWW 110
Cdd:cd11809     2 ATAQFDYTGRSERELSFKKGDSLTLYRQVSDDWW 35