Src homology 3 domain of RUN and SH3 domain-containing protein 1; RUSC1, also called NESCA (New molecule containing SH3 at the carboxy-terminus), is highly expressed in the brain and is translocated to the nuclear membrane from the cytoplasm upon stimulation with neurotrophin. It plays a role in facilitating neurotrophin-dependent neurite outgrowth. It also interacts with NEMO (or IKKgamma) and may function in NEMO-mediated activation of NF-kB. RUSC proteins are adaptor proteins consisting of RUN, leucine zipper, and SH3 domains. 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 578800776 879 AVRALCDHTAARpDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGYTS 930
Cdd:cd11958    1 AVRALCDHAGSE-SQLSFRKGEELQVLGTVDEDWIRCRRGDREGLVPVGYTS 51

Src homology 3 domain of RUN and SH3 domain-containing protein 1; RUSC1, also called NESCA (New molecule containing SH3 at the carboxy-terminus), is highly expressed in the brain and is translocated to the nuclear membrane from the cytoplasm upon stimulation with neurotrophin. It plays a role in facilitating neurotrophin-dependent neurite outgrowth. It also interacts with NEMO (or IKKgamma) and may function in NEMO-mediated activation of NF-kB. RUSC proteins are adaptor proteins consisting of RUN, leucine zipper, and SH3 domains. 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 578800776 879 AVRALCDHTAARpDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGYTS 930
Cdd:cd11958    1 AVRALCDHAGSE-SQLSFRKGEELQVLGTVDEDWIRCRRGDREGLVPVGYTS 51

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.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|
gi 578800776   880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRC-GRDGMEGLVPVGY 928
Cdd:smart00326   5 VRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGrLGRGKEGLFPSNY 54

large tegument protein UL36; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 578800776   29 RPELQEGPLSTPPPPGDTGGKESRGPCSGTLVD-ANSNSPAVPCRCCQEHGPGLENRQDPSQEEEGAASPSDPGCSSSLS 107
Cdd:PHA03247 2700 DPPPPPPTPEPAPHALVSATPLPPGPAAARQASpALPAAPAPPAVPAGPATPGGPARPARPPTTAGPPAPAPPAAPAAGP 2779

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 578800776  108 SCSDLSPDESPVSVYLRDLPGDEDAHPQPSIIPleqgsPLASAGPGTCSPDSFCCSPDSCSGASSSPDPG 177
Cdd:PHA03247 2780 PRRLTRPAVASLSESRESLPSPWDPADPPAAVL-----APAAALPPAASPAGPLPPPTSAQPTAPPPPPG 2844

RUN domain found in RUN and SH3 domain-containing proteins, RUSC1, RUSC2 and similar proteins; RUSC1, also called new molecule containing SH3 at the carboxy-terminus (NESCA), may acts as a signaling adapter that translocates to the nuclear envelope and regulates neurotrophin-induced neurite outgrowth. RUSC2, also called iporin, or interacting protein of Rab1, is a novel interacting molecule for the active GTP-bound conformation of Rab1. It may function as a link between the targeting of endoplasmic reticulum derived vesicles, triggered by the Rab1 GTPase and a signaling pathway regulated by molecules containing SH3 and/or poly-proline regions. This model contains the RUN domain of RUSC1 and RUSC2.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 578800776 620 QKKGLLIAVSVSVDKIISHFGAARNLVQKAQLGDSRLSPDVGHLVLTTLCPALHALVADGLKPFRKDLItGQRRSSPWSV 699
Cdd:cd17685    1 QKRGLVKAVIAAVDKIVAHFSQSRDPSDKAKLGNSAVSPEVGHLVLKYLCPALYALLSDGLKPYVLTLF-GQVKNSVWSV 79

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 578800776 700 VEASVKPGSSTRSLGTLYSQVSRLAPLSSSRSRFHAFILGLLNTKQLELWFSSLQ 754
Cdd:cd17685   80 VEASTQPGPSTKALNELVNKLNSEEKLTSGTLKFNAFIFGLLNLRSLDAWLSYLV 134

Src homology 3 domain of RUN and SH3 domain-containing protein 1; RUSC1, also called NESCA (New molecule containing SH3 at the carboxy-terminus), is highly expressed in the brain and is translocated to the nuclear membrane from the cytoplasm upon stimulation with neurotrophin. It plays a role in facilitating neurotrophin-dependent neurite outgrowth. It also interacts with NEMO (or IKKgamma) and may function in NEMO-mediated activation of NF-kB. RUSC proteins are adaptor proteins consisting of RUN, leucine zipper, and SH3 domains. 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 578800776 879 AVRALCDHTAARpDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGYTS 930
Cdd:cd11958    1 AVRALCDHAGSE-SQLSFRKGEELQVLGTVDEDWIRCRRGDREGLVPVGYTS 51

RUN domain; RUN domain, named after RPIP8 (Rap2 interacting protein 8), UNC-14 and NESCA (new molecule containing SH3 at the carboxyl-terminus), is a less conserved protein motif that comprises six conserved regions, which in some proteins have considerable insertions between them. The domain core is thought to take up a predominantly alpha fold, with basic amino acids in regions A and D possibly playing a functional role in interactions with Ras GTPases. RUN domains are often found in proteins linked particularly to the functions of GTPases in the Rap and Rab families, suggesting the RUN domain may be involved in Rab-mediated membrane trafficking, possibly as a Rab-binding site. RUN domain-containing proteins could hence play important roles in multiple Ras-like GTPase signalling pathways.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 578800776 630 VSVDKIISHFGAARNLVQKAQLgdsrlSPDVGHLVLTTLCPALHALVADGLKPFRKdlitGQRRSSPWSVVEASVKPGSS 709
Cdd:cd17671    1 KAVKELLESFADNGEADDSAAL-----TLTDDDPVVGRLCAALEAILSHGLKPKRF----GGGKVSFWDFLEALEKLLPA 71

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*...
gi 578800776 710 TRSLGTLYSqVSRLAPLSSSRSRFHAFILGLLNTKQLELWFSSLQEDA 757
Cdd:cd17671   72 PSLKQAIRD-INSLSNVKTDDGRGRAWIRLALNEKSLESYLAALLSDQ 118

RUN domain; This domain is present in several proteins that are linked to the functions of GTPases in the Rap and Rab families. They could hence play important roles in multiple Ras-like GTPase signalling pathways. The domain is comprises six conserved regions, which in some proteins have considerable insertions between them. The domain core is thought to take up a predominantly alpha fold, with basic amino acids in regions A and D possibly playing a functional role in interactions with Ras GTPases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 578800776  667 TLCPALHALVADGLKP---FRKDLITGQRRSSPWSVVEASVKPGSSTRSLGTLYSQVSRLAPLSSSRSRFHAFILGLLNT 743
Cdd:pfam02759   1 QLCAALEALLSHGLKRsslLILRAAGLLPERSFWALLERVGKLVPPAEELLSSVQELEQIHTPYSPDGRGRAWIRLALNE 80

                          90
                  ....*....|...
gi 578800776  744 KQLELWFSSLQED 756
Cdd:pfam02759  81 KLLDQWLKLLLSN 93

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRcGR--DGMEGLVPVGY 928
Cdd:cd00174    2 ARALYDYEAQDDDELSFKKGDIITVLEKDDDGWWE-GElnGGREGLFPANY 51

Src Homology 3 domain of metazoan osteoclast stimulating factor 1; OSTF1, also named OSF or SH3P2, is a signaling protein containing SH3 and ankyrin-repeat domains. It acts through a Src-related pathway to enhance the formation of osteoclasts and bone resorption. It also acts as a negative regulator of cell motility. 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11772    2 FRALYDYEAQHPDELSFEEGDLLYISDKSDPNWWKATCGGKTGLIPSNY 50

Variant SH3 domain; SH3 (Src homology 3) domains are often indicative of a protein involved in signal transduction related to cytoskeletal organization. First described in the Src cytoplasmic tyrosine kinase. The structure is a partly opened beta barrel.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 578800776  880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVP 925
Cdd:pfam07653   2 GRVIFDYVGTDKNGLTLKKGDVVKVLGKDNDGWWEGETGGRVGLVP 47

Src homology 3 domain of Proline-Serine-Threonine Phosphatase-Interacting Protein 1; PSTPIP1, also called CD2 Binding Protein 1 (CD2BP1), is mainly expressed in hematopoietic cells. It is a binding partner of the cell surface receptor CD2 and PTP-PEST, a tyrosine phosphatase which functions in cell motility and Rac1 regulation. It also plays a role in the activation of the Wiskott-Aldrich syndrome protein (WASP), which couples actin rearrangement and T cell activation. Mutations in the gene encoding PSTPIP1 cause the autoinflammatory disorder known as PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, and acne) syndrome. PSTPIP1 contains an N-terminal F-BAR domain, PEST motifs, 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11824    3 SVLYDYTAQEDDELSISKGDVVAVIEKGEDGWWTVERNGQKGLVPGTY 50

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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 578800776 885 DHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGYTSL 931
Cdd:cd11809    7 DYTGRSERELSFKKGDSLTLYRQVSDDWWRGQLNGQDGLVPHKYITL 53

C-terminal Src homology 3 domain of Growth factor receptor-bound protein 2 (GRB2) and related proteins; This family includes the adaptor protein GRB2 and related proteins including Drosophila melanogaster Downstream of receptor kinase (DRK), Caenorhabditis elegans Sex muscle abnormal protein 5 (Sem-5), GRB2-related adaptor protein (GRAP), GRAP2, and similar proteins. Family members contain an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. GRB2/Sem-5/DRK is a critical signaling molecule that regulates the Ras pathway by linking tyrosine kinases to the Ras guanine nucleotide releasing protein Sos (son of sevenless), which converts Ras to the active GTP-bound state. GRAP2 plays an important role in T cell receptor (TCR) signaling by promoting the formation of the SLP-76:LAT complex, which couples the TCR to the Ras pathway. GRAP acts as a negative regulator of T cell receptor (TCR)-induced lymphocyte proliferation by downregulating the signaling to the Ras/ERK pathway. The C-terminal SH3 domains (SH3c) of GRB2 and GRAP2 have been shown to bind to classical PxxP motif ligands, as well as to non-classical motifs. GRB2 SH3c binds Gab2 (Grb2-associated binder 2) through epitopes containing RxxK motifs, while the SH3c of GRAP2 binds to the phosphatase-like protein HD-PTP via a RxxxxK motif. SH3 domains are protein interaction domains that typically 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11805    2 VQALYDFNPQEPGELEFRRGDIITVLDSSDPDWWKGELRGRVGIFPANY 50

Src homology 3 domain of Protein kinase C and Casein kinase Substrate in Neurons (PACSIN) proteins; PACSINs, also called Synaptic dynamin-associated proteins (Syndapins), act as regulators of cytoskeletal and membrane dynamics. They bind both dynamin and Wiskott-Aldrich syndrome protein (WASP), and may provide direct links between the actin cytoskeletal machinery through WASP and dynamin-dependent endocytosis. Vetebrates harbor three isoforms with distinct expression patterns and specific functions. PACSINs contain an N-terminal F-BAR 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDED-WLRCGRDGMEGLVPVGY 928
Cdd:cd11843    2 VRALYDYEGQESDELSFKAGDILTKLEEEDEQgWCKGRLDGRVGLYPANY 51

Fifth Src homology 3 domain (or SH3E) of Intersectin-2; Intersectin-2 (ITSN2) is an adaptor protein that functions in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. It plays a role in clathrin-coated pit (CCP) formation. It binds to many proteins through its multidomain structure and facilitate the assembly of multimeric complexes. ITSN2 also functions as a specific GEF for Cdc42 activation in epithelial morphogenesis, and is required in mitotic spindle orientation. It exists in alternatively spliced short and long isoforms. The short isoform contains two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoform, in addition, contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. The fifth SH3 domain (or SH3E) of ITSN2 is expected to bind protein partners, similar to ITSN1 which has been shown to bind many protein partners including SGIP1, Sos1, dynamin1/2, CIN85, c-Cbl, SHIP2, N-WASP, and synaptojanin-1, among others. 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGYTSL 931
Cdd:cd11996    3 VIAMYDYTANNEDELSFSKGQLINVLNKDDPDWWQGEINGVTGLFPSNYVKM 54

C-terminal Src homology 3 domain of GRB2-related adaptor protein 2; GRAP2 is also called GADS (GRB2-related adapter downstream of Shc), GrpL, GRB2L, Mona, or GRID (Grb2-related protein with insert domain). It is expressed specifically in the hematopoietic system. It plays an important role in T cell receptor (TCR) signaling by promoting the formation of the SLP-76:LAT complex, which couples the TCR to the Ras pathway. It also has roles in antigen-receptor and tyrosine kinase mediated signaling. GRAP2 is unique from other GRB2-like adaptor proteins in that it can be regulated by caspase cleavage. It contains an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. The C-terminal SH3 domain of GRAP2 binds to different motifs found in substrate peptides including the typical PxxP motif in hematopoietic progenitor kinase 1 (HPK1), the RxxK motif in SLP-76 and HPK1, and the RxxxxK motif in phosphatase-like protein HD-PTP. SH3 domains are protein interaction domains that typically 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGYT 929
Cdd:cd11950    2 VRALYDFEALEDDELGFNSGDVIEVLDSSNPSWWKGRLHGKLGLFPANYV 51

N-terminal Src Homology 3 domain of Ct10 Regulator of Kinase adaptor proteins; CRK adaptor proteins consists of SH2 and SH3 domains, which bind tyrosine-phosphorylated peptides and proline-rich motifs, respectively. They function downstream of protein tyrosine kinases in many signaling pathways started by various extracellular signals, including growth and differentiation factors. Cellular CRK (c-CRK) contains a single SH2 domain, followed by N-terminal and C-terminal SH3 domains. It is involved in the regulation of many cellular processes including cell growth, motility, adhesion, and apoptosis. CRK has been implicated in the malignancy of various human cancers. The N-terminal SH3 domain of CRK binds a number of target proteins including DOCK180, C3G, SOS, and cABL. The CRK family includes two alternatively spliced protein forms, CRKI and CRKII, that are expressed by the CRK gene, and the CRK-like (CRKL) protein, which is expressed by a distinct gene (CRKL). 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRC-GRDGMEGLVPVGY 928
Cdd:cd11758    3 VRALFDFPGNDDEDLPFKKGEILTVIRKPEEQWWNArNSEGKTGMIPVPY 52

Src homology 3 domain of CAS (Crk-Associated Substrate) scaffolding protein family member, Embryonal Fyn-associated Substrate; EFS is also called HEFS, CASS3 (Cas scaffolding protein family member 3) or SIN (Src-interacting protein). It was identified based on interactions with the Src kinases, Fyn and Yes. It plays a role in thymocyte development and acts as a negative regulator of T cell proliferation. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure that includes an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. The SH3 domain of CAS proteins binds to diverse partners including FAK, FRNK, Pyk2, PTP-PEST, DOCK180, among others. 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITTVDED---WLRCGRDGMEGLVP 925
Cdd:cd12003    4 KALYDNAAESPEELSFRRGDVLMVLKREHGSlpgWWLCSLHGQQGIAP 51

Src homology 3 domain of Abl Interactor proteins; Abl interactor (Abi) proteins are adaptor proteins serving as binding partners and substrates of Abl tyrosine kinases. They are involved in regulating actin cytoskeletal reorganization and play important roles in membrane-ruffling, endocytosis, cell motility, and cell migration. They localize to sites of actin polymerization in epithelial adherens junction and immune synapses, as well as to the leading edge of lamellipodia. Vertebrates contain two Abi proteins, Abi1 and Abi2. Abi1 displays a wide expression pattern while Abi2 is highly expressed in the eye and brain. Abi proteins contain a homeobox homology domain, a proline-rich region, and a SH3 domain. The SH3 domain of Abi binds to a PxxP motif in Abl. 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11826    2 VVALYDYTADKDDELSFQEGDIIYVTKKNDDGWYEGVLNGVTGLFPGNY 50

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDW--LRCGRDGMEGLVPVGY 928
Cdd:cd11845    2 YVALYDYEARTDDDLSFKKGDRLQILDDSDGDWwlARHLSTGKEGYIPSNY 52

Src homology 3 domains of the p47phox subunit of NADPH oxidase and similar domains; This family is composed of the tandem SH3 domains of p47phox subunit of NADPH oxidase and Nox Organizing protein 1 (NoxO1), the four SH3 domains of Tks4 (Tyr kinase substrate with four SH3 domains), the five SH3 domains of Tks5, the SH3 domain of obscurin, Myosin-I, and similar domains. Most members of this group also contain Phox homology (PX) domains, except for obscurin and Myosin-I. p47phox and NoxO1 are regulators of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) and nonphagocytic NADPH oxidase Nox1, respectively. They play roles in the activation of their respective NADPH oxidase, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Tks proteins are Src substrates and scaffolding proteins that play important roles in the formation of podosomes and invadopodia, the dynamic actin-rich structures that are related to cell migration and cancer cell invasion. Obscurin is a giant muscle protein that plays important roles in the organization and assembly of the myofibril and the sarcoplasmic reticulum. 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. 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11856    3 VAIADYEAQGDDEISLQEGEVVEVLEKNDSGWWYVRKGDKEGWVPASY 50

Src Homology 3 domain of Sorting Nexin 9 and similar proteins; Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. This subfamily consists of SH3 domain containing SNXs including SNX9, SNX18, SNX33, and similar proteins. SNX9 is localized to plasma membrane endocytic sites and acts primarily in clathrin-mediated endocytosis, while SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1. 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.

                         10        20        30        40        50
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gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVIT-TVDEDWLRcGRD--GMEGLVPVGY 928
Cdd:cd11763    2 VRALYDFDSQPSGELSLRAGEVLTITRqDVGDGWLE-GRNsrGEVGLFPSSY 52

C-terminal Src Homology 3 domain of LIM and SH3 domain protein 1; Lasp1 is a cytoplasmic protein that binds focal adhesion proteins and is involved in cell signaling, migration, and proliferation. It is overexpressed in several cancer cells including breast, ovarian, bladder, and liver. In cancer cells, it can be found in the nucleus; its degree of nuclear localization correlates with tumor size and poor prognosis. Lasp1 is a 36kD protein containing an N-terminal LIM domain, two nebulin repeats, 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 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITTVDEDWL--RCGRDGMEGLVPVGY 928
Cdd:cd11934    6 RAVYDYNAADEDEVSFQDGDTIVNVQQIDDGWMygTVERTGDTGMLPANY 55

Src homology 3 domain of ArfGAP with SH3 domain, ankyrin repeat and PH domain containing proteins; ASAPs are Arf GTPase activating proteins (GAPs) and they function in regulating cell growth, migration, and invasion. They contain an N-terminal BAR domain, followed by a Pleckstrin homology (PH) domain, an Arf GAP domain, ankyrin (ANK) repeats, and a C-terminal SH3 domain. Vertebrates contain at least three members, ASAP1, ASAP2, and ASAP3, but some ASAP3 proteins do not seem to harbor a C-terminal SH3 domain. ASAP1 and ASAP2 show GTPase activating protein (GAP) activity towards Arf1 and Arf5. They do not show GAP activity towards Arf6, but are able to mediate Arf6 signaling by binding stably to GTP-Arf6. ASAP3 is an Arf6-specific GAP. 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.

                         10        20        30
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gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDW 912
Cdd:cd11821    2 VRALYDCQADNDDELTFSEGEIIVVTGEEDDEW 34

C-terminal Src homology 3 domain of Growth factor receptor-bound protein 2; GRB2 is a critical signaling molecule that regulates the Ras pathway by linking tyrosine kinases to the Ras guanine nucleotide releasing protein Sos (son of sevenless), which converts Ras to the active GTP-bound state. It is ubiquitously expressed in all tissues throughout development and is important in cell cycle progression, motility, morphogenesis, and angiogenesis. In lymphocytes, GRB2 is associated with antigen receptor signaling components. GRB2 contains an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. The C-terminal SH3 domain of GRB2 binds to Gab2 (Grb2-associated binder 2) through epitopes containing RxxK motifs, as well as to the proline-rich C-terminus of FGRF2. SH3 domains are protein interaction domains that typically 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 578800776 879 AVRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11949    1 YVQALFDFDPQEDGELGFRRGDFIEVMDNSDPNWWKGACHGQTGMFPRNY 50

First Src Homology 3 domain of SH3 domain containing ring finger proteins; This model represents the first SH3 domain of SH3RF1 (or POSH), SH3RF2 (or POSHER), SH3RF3 (POSH2), and similar domains. Members of this family are scaffold proteins that function as E3 ubiquitin-protein ligases. They all contain an N-terminal RING finger domain and multiple SH3 domains; SH3RF1 and SH3RF3 have four SH3 domains while SH3RF2 has three. SH3RF1 plays a role in calcium homeostasis through the control of the ubiquitin domain protein Herp. It may also have a role in regulating death receptor mediated and JNK mediated apoptosis. SH3RF3 interacts with p21-activated kinase 2 (PAK2) and GTP-loaded Rac1. It may play a role in regulating JNK mediated apoptosis in certain conditions. SH3RF2 acts as an anti-apoptotic regulator of the JNK pathway by binding to and promoting the degradation of SH3RF1. 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.

                         10        20        30        40
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gi 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11786    3 KALYNYEGKEPGDLSFKKGDIILLRKRIDENWYHGECNGKQGFFPASY 50

C-terminal Src Homology 3 domain of the Nebulin family of proteins; Nebulin family proteins contain multiple nebulin repeats, and may contain an N-terminal LIM domain and/or a C-terminal SH3 domain. They have molecular weights ranging from 34 to 900 kD, depending on the number of nebulin repeats, and they all bind actin. They are involved in the regulation of actin filament architecture and function as stabilizers and scaffolds for cytoskeletal structures with which they associate, such as long actin filaments or focal adhesions. Nebulin family proteins that contain a C-terminal SH3 domain include the giant filamentous protein nebulin, nebulette, Lasp1, and Lasp2. Lasp2, also called LIM-nebulette, is an alternatively spliced variant of nebulette. 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 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWL--RCGRDGMEGLVPVGY 928
Cdd:cd11789    2 YRAMYDYAAADDDEVSFQEGDVIINVEIIDDGWMegTVQRTGQSGMLPANY 52

Src homology 3 domain of Endophilin-B; Endophilins play roles in synaptic vesicle formation, virus budding, mitochondrial morphology maintenance, receptor-mediated endocytosis inhibition, and endosomal sorting. They are classified into two types, A and B. Vertebrates contain two endophilin-B isoforms. Endophilin-B proteins are cytoplasmic proteins expressed mainly in the heart, placenta, and skeletal muscle. Endophilins contain an N-terminal N-BAR domain (BAR domain with an additional N-terminal amphipathic helix), followed by a variable region containing proline clusters, 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 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITT--VDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11802    3 RVLYDYDAEDSTELSLLADEVITVYELpgMDEDYMMGERGSQRGKVPVAY 52

Fifth Src homology 3 domain (or SH3E) of Intersectin-1; Intersectin-1 (ITSN1) is an adaptor protein that functions in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. It plays a role in clathrin-coated pit (CCP) formation. It binds to many proteins through its multidomain structure and facilitate the assembly of multimeric complexes. ITSN1 localizes in membranous organelles, CCPs, the Golgi complex, and may be involved in the cell membrane trafficking system. It exists in alternatively spliced short and long isoforms. The short isoform contains two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoform, in addition, contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. The fifth SH3 domain (or SH3E) of ITSN1 has been shown to bind many protein partners including SGIP1, Sos1, dynamin1/2, CIN85, c-Cbl, SHIP2, N-WASP, and synaptojanin-1, among others. 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 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGYTSL 931
Cdd:cd11995    3 VIGMYDYTAQNDDELAFSKGQIINVLNKEDPDWWKGELNGQVGLFPSNYVKL 54

Third Src Homology 3 domain of Nck adaptor proteins; This group contains the third SH3 domain of Nck, the first SH3 domain of Caenorhabditis elegans Ced-2 (Cell death abnormality protein 2), and similar domains. Nck adaptor proteins regulate actin cytoskeleton dynamics by linking proline-rich effector molecules to protein tyrosine kinases and phosphorylated signaling intermediates. They contain three SH3 domains and a C-terminal SH2 domain. They function downstream of the PDGFbeta receptor and are involved in Rho GTPase signaling and actin dynamics. Vertebrates contain two Nck adaptor proteins: Nck1 (also called Nckalpha) and Nck2 (also called Nckbeta or Growth factor receptor-bound protein 4, Grb4), which show partly overlapping functions but also bind distinct targets. Their SH3 domains are involved in recruiting downstream effector molecules, such as the N-WASP/Arp2/3 complex, which when activated induces actin polymerization that results in the production of pedestals, or protrusions of the plasma membrane. The third SH3 domain of Nck appears to prefer ligands with a PxAPxR motif. SH3 domains are protein interaction domains that usually bind to proline-rich ligands with moderate affinity and selectivity, preferentially a PxxP motif. Ced-2 is a cell corpse engulfment protein that interacts with Ced-5 in a pathway that regulates the activation of Ced-10, a Rac small GTPase.

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gi 578800776 879 AVRALCDHTAARPDQLSFRRGEVLRVI--TTVDEDWLRC-GRDGMEGLVPVGYTSL 931
Cdd:cd11767    1 VVVALYPFTGENDEELSFEKGERLEIIekPEDDPDWWKArNALGTTGLVPRNYVEV 56

Third N-terminal Src homology 3 domain of Dynamin Binding Protein, also called Tuba; DNMBP or Tuba is a cdc42-specific guanine nucleotide exchange factor (GEF) that contains four N-terminal SH3 domains, a central RhoGEF [or Dbl homology (DH)] domain followed by a Bin/Amphiphysin/Rvs (BAR) domain, and two C-terminal SH3 domains. It provides a functional link between dynamin and key regulatory proteins of the actin cytoskeleton. It plays an important role in regulating cell junction configuration. The four N-terminal SH3 domains of DNMBP binds the GTPase dynamin, which plays an important role in the fission of endocytic vesicles. 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 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11796    3 RVLQDLSAQLDEELDLREGDVVTITGILDKGWFRGELNGRRGIFPEGF 50

C-terminal Src Homology 3 domain of NADPH oxidase activator 1; Noxa1 is a homolog of p67phox and is a cytosolic subunit of the nonphagocytic NADPH oxidase complex Nox1, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Noxa1 is co-expressed with Nox1 in colon, stomach, uterus, prostate, and vascular smooth muscle cells, consistent with its regulatory role. It does not interact with p40phox, unlike p67phox, making Nox1 activity independent of p40phox, unlike Nox2. Noxa1 contains TPR, PB1, and C-terminal SH3 domains, but lacks the central SH3 domain that is present in p67phox. The TPR domain binds activated GTP-bound Rac. The C-terminal SH3 domain binds the polyproline motif found at the C-terminus of Noxo1, a homolog of p47phox. 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.

                         10        20        30        40
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gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVP 925
Cdd:cd12047    2 MVAQHDYSAQGPEDLEFSQGDTIDILSEVNQEWLEGHCDGRIGIFP 47

Src Homology 3 domain of GTPase Regulator Associated with Focal adhesion kinase and similar proteins; This subfamily is composed of Rho GTPase activating proteins (GAPs) with similarity to GRAF. Members contain an N-terminal BAR domain, followed by a Pleckstrin homology (PH) domain, a Rho GAP domain, and a C-terminal SH3 domain. Although vertebrates harbor four Rho GAPs in the GRAF subfamily including GRAF, GRAF2, GRAF3, and Oligophrenin-1 (OPHN1), only three are included in this model. OPHN1 contains the BAR, PH and GAP domains, but not the C-terminal SH3 domain. GRAF and GRAF2 show GAP activity towards RhoA and Cdc42. GRAF influences Rho-mediated cytoskeletal rearrangements and binds focal adhesion kinase. GRAF2 regulates caspase-activated p21-activated protein kinase-2. The SH3 domain of GRAF and GRAF2 binds PKNbeta, a target of the small GTPase Rho. 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 578800776 880 VRALCDHTAARPDQLSFRRGEVL-RVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11882    2 ARALYACKAEDESELSFEPGQIItNVQPSDEPGWLEGTLNGRTGLIPENY 51

Fourth Src homology 3 domain of ADAM-binding protein Eve-1; Eve-1, also called SH3 domain-containing protein 19 (SH3D19) or EEN-binding protein (EBP), exists in multiple alternatively spliced isoforms. The longest isoform contains five SH3 domain in the C-terminal region and seven proline-rich motifs in the N-terminal region. It is abundantly expressed in skeletal muscle and heart, and may be involved in regulating the activity of ADAMs (A disintegrin and metalloproteases). Eve-1 interacts with EEN, an endophilin involved in endocytosis and may be the target of the MLL-EEN fusion protein that is implicated in leukemogenesis. 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.

                         10        20        30        40
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gi 578800776 882 ALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11817    4 ALYDFTGETEEDLSFQRGDRILVTEHLDAEWSRGRLNGREGIFPRAF 50

Second Src Homology 3 domain of Sorbin and SH3 domain containing (Sorbs) proteins and similar domains; This family, also called the vinexin family, is composed predominantly of adaptor proteins containing one sorbin homology (SoHo) and three SH3 domains. Members include the second SH3 domains of Sorbs1 (or ponsin), Sorbs2 (or ArgBP2), Vinexin (or Sorbs3), and similar domains. They are involved in the regulation of cytoskeletal organization, cell adhesion, and growth factor signaling. Members of this family bind multiple partners including signaling molecules like c-Abl, c-Arg, Sos, and c-Cbl, as well as cytoskeletal molecules such as vinculin and afadin. They may have overlapping functions. 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 578800776 881 RALCDHTAARPDQLSFRRGEVLRVITTVDEDWLRCGRDGMEGLVPVGY 928
Cdd:cd11782    3 RAKYNFNADTGVELSFRKGDVITLTRRVDENWYEGRIGGRQGIFPVSY 50

Src Homology 3 domain of CSK homologous kinase; CHK is also referred to as megakaryocyte-associated tyrosine kinase (Matk). It inhibits Src kinases using a noncatalytic mechanism by simply binding to them. As a negative regulator of Src kinases, Chk may play important roles in cell proliferation, survival, and differentiation, and consequently, in cancer development and progression. To inhibit Src kinases that are anchored to the plasma membrane, CHK is translocated to the membrane via binding to specific transmembrane proteins, G-proteins, or adaptor proteins near the membrane. CHK also plays a role in neural differentiation in a manner independent of Src by enhancing MAPK activation via Ras-mediated signaling. It is a cytoplasmic (or nonreceptor) tyr kinase containing the Src homology domains, SH3 and SH2, N-terminal to the catalytic tyr kinase 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 578800776 884 CDHTAARPDQLSFRRGEVLRVITTVDE-DWLRCGRD--GMEGLVPVG 927
Cdd:cd11811    8 KDHTKPKPGELAFHKGDIVTIVETCERkGWYRARHNtsGEEGLVAAG 54

Src Homology 3 (SH3) domain of Inhibitor of ASPP protein (iASPP); iASPP, also called RelA-associated inhibitor (RAI), is an oncoprotein that inhibits the apoptotic transactivation potential of p53. It is upregulated in human breast cancers expressing wild-type p53, in acute leukemias regardless of the p53 mutation status, as well as in ovarian cancer where it is associated with poor patient outcome and chemoresistance. iASPP is also a binding partner and negative regulator of p65RelA, which promotes cell proliferation and inhibits apoptosis; p65RelA has the opposite effect on cell growth compared to the p53 family. It contains a proline-rich region, four ankyrin (ANK) repeats, and an SH3 domain at its C-terminal half. The SH3 domain and the ANK repeats of iASPP contribute to the p53 binding site; they bind to the DNA binding domain of p53. 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 578800776 879 AVRALCDHTAARPDQLSFRRGEVLRVITTVDE--DWLRCGRDGMEGLVPVGYTSL 931
Cdd:cd11952    2 VVYALWDYSAEFPDELSFKEGDMVTVLRKDGEgtDWWWASLCGREGYVPRNYFGL 56

Src homology 3 domain of CAS (Crk-Associated Substrate) scaffolding protein family member, Neural precursor cell Expressed, Developmentally Down-regulated 9; NEDD9 is also called human enhancer of filamentation 1 (HEF1) or CAS-L (Crk-associated substrate in lymphocyte). It was first described as a gene predominantly expressed in early embryonic brain, and was also isolated from a screen of human proteins that regulate filamentous budding in yeast, and as a tyrosine phosphorylated protein in lymphocytes. It promotes metastasis in different solid tumors. NEDD9 localizes in focal adhesions and associates with FAK and Abl kinase. It also interacts with SMAD3 and the proteasomal machinery which allows its rapid turnover; these interactions are not shared by other CAS proteins. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure that includes an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. The SH3 domain of CAS proteins binds to diverse partners including FAK, FRNK, Pyk2, PTP-PEST, DOCK180, among others. 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.

                         10        20        30        40
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gi 578800776 881 RALCDHTAARPDQLSFRRGEVLRVI---TTVDEDWLRCGRDGMEGLVP 925
Cdd:cd12002    3 RALYDNVPECAEELAFRKGDILTVIeqnTGGLEGWWLCSLHGRQGIAP 50

Src homology 3 domain of Phospholipase C (PLC) gamma; PLC catalyzes the hydrolysis of phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] to produce Ins(1,4,5)P3 and diacylglycerol (DAG) in response to various receptors. Ins(1,4,5)P3 initiates the calcium signaling cascade while DAG functions as an activator of PKC. PLCgamma catalyzes this reaction in tyrosine kinase-dependent signaling pathways. It is activated and recruited to its substrate at the membrane. Vertebrates contain two forms of PLCgamma, PLCgamma1, which is widely expressed, and PLCgamma2, which is primarily found in haematopoietic cells. PLCgamma contains a Pleckstrin homology (PH) domain followed by an elongation factor (EF) domain, two catalytic regions of PLC domains that flank two tandem SH2 domains, followed by a SH3 domain and C2 domain. The SH3 domain of PLCgamma1 directly interacts with dynamin-1 and can serve as a guanine nucleotide exchange factor (GEF). It also interacts with Cbl, inhibiting its phosphorylation and activity. 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 578800776 879 AVRALCDHTAARPDQLSFRRGEVLRVITTVDEDWLR--CGrDGMEGLVPVGYT 929
Cdd:cd11825    1 TVKALYDYRAQRPDELSFCKHAIITNVEKEDGGWWRgdYG-GKKQKWFPANYV 52

Src homology 3 domain of Disks Large homolog 5; DLG5 is a multifunctional scaffold protein that is located at sites of cell-cell contact and is involved in the maintenance of cell shape and polarity. Mutations in the DLG5 gene are associated with Crohn's disease (CD) and inflammatory bowel disease (IBD). DLG5 is a member of the MAGUK (membrane-associated guanylate kinase) protein family, which is characterized by the presence of a core of three domains: PDZ, SH3, and guanylate kinase (GuK). The GuK domain in MAGUK proteins is enzymatically inactive; instead, the domain mediates protein-protein interactions and associates intramolecularly with the SH3 domain. DLG5 contains 4 PDZ domains as well as an N-terminal domain of unknown function. 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.

                         10        20
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gi 578800776 880 VRALCDHTAARPDQLSFRRGEVLRVITTV 908
Cdd:cd11860    2 VRALFDRSAENEDELSFKKDDILYVDNTM 30

Src homology 3 domain of Endophilin-B1; Endophilin-B1, also called Bax-interacting factor 1 (Bif-1) or SH3GLB1 (SH3-domain GRB2-like endophilin B1), is localized mainly to the Golgi apparatus. It is involved in the regulation of many biological events including autophagy, tumorigenesis, nerve growth factor (NGF) trafficking, neurite outgrowth, mitochondrial outer membrane dynamics, and cell death. Endophilins play roles in synaptic vesicle formation, virus budding, mitochondrial morphology maintenance, receptor-mediated endocytosis inhibition, and endosomal sorting. They contain an N-terminal N-BAR domain (BAR domain with an additional N-terminal amphipathic helix), followed by a variable region containing proline clusters, and a C-terminal SH3 domain. Endophilin-B1 forms homo- and heterodimers (with endophilin-B2) through its BAR domain. It interacts with amphiphysin 1 and dynamin 1 through its 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 578800776 878 RAVRALCDHTAARPDQLSFRRGEVLRV--ITTVDEDWLRCGRDGMEGLVPVGYTSLV 932
Cdd:cd11945    4 RKARVLYDYDAANSTELSLLADEVITVysVPGMDSDWLMGERGNQKGKVPITYLELL 60