Src homology 3 domain of Ubiquitin-associated and SH3 domain-containing protein A; UBASH3A is also called Cbl-Interacting Protein 4 (CLIP4), T cell Ubiquitin LigAnd (TULA), or T cell receptor Signaling (STS)-2. It is only found in lymphoid cells and exhibits weak phosphatase activity. UBASH3A facilitates T cell-induced apoptosis through interaction with the apoptosis-inducing factor AIF. It is involved in regulating the level of phosphorylation of the zeta-associated protein (ZAP)-70 tyrosine kinase. TULA proteins contain an N-terminal UBA domain, a central SH3 domain, and a C-terminal histidine phosphatase domain. They bind c-Cbl through the SH3 domain and to ubiquitin via UBA. 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971 279 QTLRALFQYKPQNVDELTLSPGDYIFVDPTQQDEASEGWVIGISQRTGCRGFLPENYTDR 338
Cdd:cd11937    1 QTLRALFQYKPQNIDELMLSPGDYIFVDPTQQSEASEGWVIGISHRTGCRGFLPENYTER 60

Histidine phosphatase domain found in phosphoglycerate mutases and related proteins, mostly phosphatases; contains a His residue which is phosphorylated during the reaction; Subgroup of the catalytic domain of a functionally diverse set of proteins, most of which are phosphatases. The conserved catalytic core of this domain contains a His residue which is phosphorylated in the reaction. This subgroup contains cofactor-dependent and cofactor-independent phosphoglycerate mutases (dPGM, and BPGM respectively), fructose-2,6-bisphosphatase (F26BP)ase, Sts-1, SixA, and related proteins. Functions include roles in metabolism, signaling, or regulation, for example, F26BPase affects glycolysis and gluconeogenesis through controlling the concentration of F26BP; BPGM controls the concentration of 2,3-BPG (the main allosteric effector of hemoglobin in human blood cells); human Sts-1 is a T-cell regulator; Escherichia coli Six A participates in the ArcB-dependent His-to-Asp phosphorelay signaling system. Deficiency and mutation in many of the human members result in disease, for example erythrocyte BPGM deficiency is a disease associated with a decrease in the concentration of 2,3-BPG.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971 398 VLVVRHGERVDQIFGkawlqqcstpdgkyyrpdlnfpcslprRSRGIKDfendPPLSSCGIFQSRIAGDALLDSGIRISS 477
Cdd:cd07067    2 LYLVRHGESEWNAEG---------------------------RFQGWTD----VPLTEKGREQARALGKRLKELGIKFDR 50

                         90
                 ....*....|....*....
gi 768020971 478 VFASPALRCVQTAKLILEG 496
Cdd:cd07067   51 IYSSPLKRAIQTAEIILEE 69

Src homology 3 domain of Ubiquitin-associated and SH3 domain-containing protein A; UBASH3A is also called Cbl-Interacting Protein 4 (CLIP4), T cell Ubiquitin LigAnd (TULA), or T cell receptor Signaling (STS)-2. It is only found in lymphoid cells and exhibits weak phosphatase activity. UBASH3A facilitates T cell-induced apoptosis through interaction with the apoptosis-inducing factor AIF. It is involved in regulating the level of phosphorylation of the zeta-associated protein (ZAP)-70 tyrosine kinase. TULA proteins contain an N-terminal UBA domain, a central SH3 domain, and a C-terminal histidine phosphatase domain. They bind c-Cbl through the SH3 domain and to ubiquitin via UBA. 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971 279 QTLRALFQYKPQNVDELTLSPGDYIFVDPTQQDEASEGWVIGISQRTGCRGFLPENYTDR 338
Cdd:cd11937    1 QTLRALFQYKPQNIDELMLSPGDYIFVDPTQQSEASEGWVIGISHRTGCRGFLPENYTER 60

Histidine phosphatase domain found in phosphoglycerate mutases and related proteins, mostly phosphatases; contains a His residue which is phosphorylated during the reaction; Subgroup of the catalytic domain of a functionally diverse set of proteins, most of which are phosphatases. The conserved catalytic core of this domain contains a His residue which is phosphorylated in the reaction. This subgroup contains cofactor-dependent and cofactor-independent phosphoglycerate mutases (dPGM, and BPGM respectively), fructose-2,6-bisphosphatase (F26BP)ase, Sts-1, SixA, and related proteins. Functions include roles in metabolism, signaling, or regulation, for example, F26BPase affects glycolysis and gluconeogenesis through controlling the concentration of F26BP; BPGM controls the concentration of 2,3-BPG (the main allosteric effector of hemoglobin in human blood cells); human Sts-1 is a T-cell regulator; Escherichia coli Six A participates in the ArcB-dependent His-to-Asp phosphorelay signaling system. Deficiency and mutation in many of the human members result in disease, for example erythrocyte BPGM deficiency is a disease associated with a decrease in the concentration of 2,3-BPG.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971 398 VLVVRHGERVDQIFGkawlqqcstpdgkyyrpdlnfpcslprRSRGIKDfendPPLSSCGIFQSRIAGDALLDSGIRISS 477
Cdd:cd07067    2 LYLVRHGESEWNAEG---------------------------RFQGWTD----VPLTEKGREQARALGKRLKELGIKFDR 50

                         90
                 ....*....|....*....
gi 768020971 478 VFASPALRCVQTAKLILEG 496
Cdd:cd07067   51 IYSSPLKRAIQTAEIILEE 69

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 768020971   279 QTLRALFQYKPQNVDELTLSPGDYIFVDptqqDEASEGWVIGISQRtGCRGFLPENY 335
Cdd:smart00326   3 PQVRALYDYTAQDPDELSFKKGDIITVL----EKSDDGWWKGRLGR-GKEGLFPSNY 54

Phosphoglycerate mutase family; Phosphoglycerate mutase (PGAM) and bisphosphoglycerate mutase (BPGM) are structurally related enzymes that catalyse reactions involving the transfer of phospho groups between the three carbon atoms of phosphoglycerate... Both enzymes can catalyse three different reactions with different specificities, the isomerization of 2-phosphoglycerate (2-PGA) to 3-phosphoglycerate (3-PGA) with 2,3-diphosphoglycerate (2,3-DPG) as the primer of the reaction, the synthesis of 2,3-DPG from 1,3-DPG with 3-PGA as a primer and the degradation of 2,3-DPG to 3-PGA (phosphatase activity). In mammals, PGAM is a dimeric protein with two isoforms, the M (muscle) and B (brain) forms. In yeast, PGAM is a tetrameric protein.

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|....*...
gi 768020971   449 NDPPLSSCGIFQSRIAGDALLD-SGIRISSVFASPALRCVQTAKLILE 495
Cdd:smart00855  22 TDVPLTELGRAQAEALGRLLASlLLPRFDVVYSSPLKRARQTAEALAI 69

RNA 2',3'-cyclic phosphodiesterase (2'-5' RNA ligase) [Translation, ribosomal structure and biogenesis];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971  76 LFLC--PTGPLLEKLQEFWRESKRQCAKNRAHEVFPHVTLCDFFTCEDQKVECLYEALKRAGDRL---------LGSFPT 144
Cdd:COG1514    3 LFIAlpPPEELREALAALRARLKAAPGGRWVRPENLHLTLAFLGEVDEERLEALAEALARAAAGAppfelrldgLGAFPR 82

                         90       100
                 ....*....|....*....|..
gi 768020971 145 AVPLALhssisYLGffVSGSPA 166
Cdd:COG1514   83 PRPRVL-----WLG--VEPSPE 97

Src homology 3 domain of Ubiquitin-associated and SH3 domain-containing protein A; UBASH3A is also called Cbl-Interacting Protein 4 (CLIP4), T cell Ubiquitin LigAnd (TULA), or T cell receptor Signaling (STS)-2. It is only found in lymphoid cells and exhibits weak phosphatase activity. UBASH3A facilitates T cell-induced apoptosis through interaction with the apoptosis-inducing factor AIF. It is involved in regulating the level of phosphorylation of the zeta-associated protein (ZAP)-70 tyrosine kinase. TULA proteins contain an N-terminal UBA domain, a central SH3 domain, and a C-terminal histidine phosphatase domain. They bind c-Cbl through the SH3 domain and to ubiquitin via UBA. 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971 279 QTLRALFQYKPQNVDELTLSPGDYIFVDPTQQDEASEGWVIGISQRTGCRGFLPENYTDR 338
Cdd:cd11937    1 QTLRALFQYKPQNIDELMLSPGDYIFVDPTQQSEASEGWVIGISHRTGCRGFLPENYTER 60

Src homology 3 domain of Ubiquitin-associated and SH3 domain-containing protein B; UBASH3B, also called Suppressor of T cell receptor Signaling (STS)-1 or T cell Ubiquitin LigAnd (TULA)-2 is an active phosphatase that is expressed ubiquitously. The phosphatase activity of UBASH3B is essential for its roles in the suppression of TCR signaling and the regulation of EGFR. It also interacts with Syk and functions as a negative regulator of platelet glycoprotein VI signaling. TULA proteins contain an N-terminal UBA domain, a central SH3 domain, and a C-terminal histidine phosphatase domain. They bind c-Cbl through the SH3 domain and to ubiquitin via UBA. 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 768020971 278 YQTLRALFQYKPQNVDELTLSPGDYIFVDPTQQDEASEGWVIGISQRTGCRGFLPENYTDRA 339
Cdd:cd11936    1 HETLQVIYPYTPQNDDELELVPGDYIFMSPMEQTSTSEGWIYGTSLTTGCSGLLPENYITKA 62

Src Homology 3 domain of Amphiphysin and related domains; Amphiphysins function primarily in endocytosis and other membrane remodeling events. They exist in several isoforms and mammals possess two amphiphysin proteins from distinct genes. Amphiphysin I proteins, enriched in the brain and nervous system, contain domains that bind clathrin, Adaptor Protein complex 2 (AP2), dynamin, and synaptojanin. They function in synaptic vesicle endocytosis. Human autoantibodies to amphiphysin I hinder GABAergic signaling and contribute to the pathogenesis of paraneoplastic stiff-person syndrome. Some amphiphysin II isoforms, also called Bridging integrator 1 (Bin1), are localized in many different tissues and may function in intracellular vesicle trafficking. In skeletal muscle, Bin1 plays a role in the organization and maintenance of the T-tubule network. Mutations in Bin1 are associated with autosomal recessive centronuclear myopathy. Amphiphysins contain an N-terminal BAR domain with an additional N-terminal amphipathic helix (an N-BAR), a variable central domain, and a C-terminal SH3 domain. The SH3 domain of amphiphysins bind proline-rich motifs present in binding partners such as dynamin, synaptojanin, and nsP3. It also belongs to a subset of SH3 domains that bind ubiquitin in a site that overlaps with the peptide binding site. 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFVDPTQ-QDEASEGWVIGISQRTGCRGFLPENYTDR 338
Cdd:cd11790    4 KVRATHDYTAEDTDELTFEKGDVILVIPFDdPEEQDEGWLMGVKESTGCRGVFPENFTER 63

Histidine phosphatase domain found in phosphoglycerate mutases and related proteins, mostly phosphatases; contains a His residue which is phosphorylated during the reaction; Subgroup of the catalytic domain of a functionally diverse set of proteins, most of which are phosphatases. The conserved catalytic core of this domain contains a His residue which is phosphorylated in the reaction. This subgroup contains cofactor-dependent and cofactor-independent phosphoglycerate mutases (dPGM, and BPGM respectively), fructose-2,6-bisphosphatase (F26BP)ase, Sts-1, SixA, and related proteins. Functions include roles in metabolism, signaling, or regulation, for example, F26BPase affects glycolysis and gluconeogenesis through controlling the concentration of F26BP; BPGM controls the concentration of 2,3-BPG (the main allosteric effector of hemoglobin in human blood cells); human Sts-1 is a T-cell regulator; Escherichia coli Six A participates in the ArcB-dependent His-to-Asp phosphorelay signaling system. Deficiency and mutation in many of the human members result in disease, for example erythrocyte BPGM deficiency is a disease associated with a decrease in the concentration of 2,3-BPG.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 768020971 398 VLVVRHGERVDQIFGkawlqqcstpdgkyyrpdlnfpcslprRSRGIKDfendPPLSSCGIFQSRIAGDALLDSGIRISS 477
Cdd:cd07067    2 LYLVRHGESEWNAEG---------------------------RFQGWTD----VPLTEKGREQARALGKRLKELGIKFDR 50

                         90
                 ....*....|....*....
gi 768020971 478 VFASPALRCVQTAKLILEG 496
Cdd:cd07067   51 IYSSPLKRAIQTAEIILEE 69

Third (or C-terminal) Src Homology 3 domain of Vinexin, also called Sorbin and SH3 domain containing 3 (Sorbs3); Vinexin is also called Sorbs3, SH3P3, and SH3-containing adapter molecule 1 (SCAM-1). It is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. Vinexin was first identified as a vinculin binding protein; it is co-localized with vinculin at cell-ECM and cell-cell adhesion sites. There are several splice variants of vinexin: alpha, which contains the SoHo and three SH3 domains and displays tissue-specific expression; and beta, which contains only the three SH3 domains and is widely expressed. Vinexin alpha stimulates the accumulation of F-actin at focal contact sites. Vinexin also promotes keratinocyte migration and wound healing. The SH3 domains of vinexin have been reported to bind a number of ligands including vinculin, WAVE2, DLG5, Abl, and Cbl. 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 768020971 279 QTLRALFQYKPQNVDELTLSPGDyiFVDPTQQdeASEGWVIGISQRTGCRGFLPENY 335
Cdd:cd11918    2 TPYKAVYQYRPQNEDELELREGD--RVDVMQQ--CDDGWFVGVSRRTQKFGTFPGNY 54

UBA1 domain found in Schizosaccharomyces pombe ubiquitin carboxyl-terminal hydrolase 14 (spUBP14) and similar proteins; spUBP14, also called deubiquitinating enzyme 14, UBA domain-containing protein 2, ubiquitin thioesterase 14, or ubiquitin-specific-processing protease 14, functions as a deubiquitinating enzyme that is involved in protein degradation in fission yeast. Members in this family contain two tandem ubiquitin-association (UBA) domains. This model corresponds to the UBA1 domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 768020971  22 PSLLEPLLAMGFPVHTALKALAATGRKTAEEALAWLHDHCNDPSLD 67
Cdd:cd14385    2 AEALAQLLGMGFPEVRCKKALLATGNSDAEAAMNWLFEHMDDPDID 47

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 768020971 280 TLRALFQYKPQNVDELTLSPGDYIfVDPTQQDEaseGWVIGISQRTGCRGFLPENY 335
Cdd:cd11789    1 RYRAMYDYAAADDDEVSFQEGDVI-INVEIIDD---GWMEGTVQRTGQSGMLPANY 52

Third (or C-terminal) Src Homology 3 domain of Sorbin and SH3 domain containing 1 (Sorbs1), also called ponsin; Sorbs1 is also called ponsin, SH3P12, or CAP (c-Cbl associated protein). It is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. It binds Cbl and plays a major role in regulating the insulin signaling pathway by enhancing insulin-induced phosphorylation of Cbl. Sorbs1, like vinexin, localizes at cell-ECM and cell-cell adhesion sites where it binds vinculin, paxillin, and afadin. It may function in the control of cell motility. Other interaction partners of Sorbs1 include c-Abl, Sos, flotillin, Grb4, ataxin-7, filamin C, 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 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFVdptqQDEASEGWVIGISQRTGCRGFLPENY 335
Cdd:cd11916    3 SYQALYSYAPQNDDELELRDGDIVDV----MEKCDDGWFVGTSRRTKQFGTFPGNY 54

Src Homology 3 domain of Bridging integrator 1 (Bin1), also called Amphiphysin-2; Bin1 isoforms are localized in many different tissues and may function in intracellular vesicle trafficking. It plays a role in the organization and maintenance of the T-tubule network in skeletal muscle. Mutations in Bin1 are associated with autosomal recessive centronuclear myopathy. Bin1 contains an N-terminal BAR domain with an additional N-terminal amphipathic helix (an N-BAR) and a C-terminal SH3 domain. The SH3 domain of Bin1 forms transient complexes with actin, myosin filaments, and CDK5, to facilitate sarcomere organization and myofiber maturation. It also binds dynamin and prevents its self-assembly. 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 768020971 281 LRALFQYKPQNVDELTLSPGDYIFVDPTQQ-DEASEGWVIGISQR--------TGCRGFLPENYTDR 338
Cdd:cd12139    5 VQAQHDYTATDTDELQLKAGDVVLVIPFQNpEEQDEGWLMGVKESdwnqhkklEKCRGVFPENFTER 71

Phosphohistidine phosphatase SixA [Signal transduction mechanisms];

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 768020971 440 RSRGIKDFenDPPLSSCGIFQSRIAGDALLDSGIRISSVFASPALRCVQTAKLILE 495
Cdd:COG2062   12 RAPGGDDF--DRPLTERGRRQARAMARWLAALGLKPDRILSSPALRARQTAEILAE 65

UBA domain found in plant PNGase/UBA or UBX (PUB) domain-containing proteins; This family includes some uncharacterized hypothetical proteins found in plants. Although their biological function remain unclear, all family members contain an N-terminal ubiquitin-associated (UBA) domain and a C-terminal PUB domain. UBA domain, along with UBL (ubiquitin-like) domain, has been implicated in proteasomal degradation by associating with substrates destined for degradation as well as with subunits of the proteasome, thus regulating protein turnover. PUB domain functions as a p97 (also known as valosin-containing protein or VCP) adaptor by interacting with the D1 and/or D2 ATPase domains. The type II AAA+ ATPase p97 is involved in a variety of cellular processes such as the deglycosylation of ERAD substrates, membrane fusion, transcription factor activation and cell cycle regulation through differential binding to specific adaptor proteins.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 768020971  24 LLEPLLAMGFPVHTALKALAATGRKTAEEALAWLHDHCNDPSLD 67
Cdd:cd14290    6 LLKELEAMGFPRARAVRALHHTGNTSVEAAVNWIVEHENDPDID 49

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 768020971 282 RALFQYKPQNVDELTLSPGDYIfVDPTQQDEaseGWVIGISQRTGCRGFLPENYTD 337
Cdd:cd11934    6 RAVYDYNAADEDEVSFQDGDTI-VNVQQIDD---GWMYGTVERTGDTGMLPANYVE 57

First Src homology 3 domain (or SH3A) of Intersectin; Intersectins (ITSNs) are adaptor proteins that function in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. They are essential for initiating clathrin-coated pit formation. They bind to many proteins through their multidomain structure and facilitate the assembly of multimeric complexes. Vertebrates contain two ITSN proteins, ITSN1 and ITSN2, which exist in alternatively spliced short and long isoforms. The short isoforms contain two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoforms, in addition, contain RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. ITSN1 and ITSN2 are both widely expressed, with variations depending on tissue type and stage of development. The first SH3 domain (or SH3A) of ITSN1 has been shown to bind many proteins including Sos1, dynamin1/2, CIN85, c-Cbl, PI3K-C2, SHIP2, N-WASP, and CdGAP, 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 768020971 282 RALFQYKPQNVDELTLSPGDYIFVDptQQDEASEGWVIGisQRTGCRGFLPENYTDR 338
Cdd:cd11836    3 RALYAFEARNPDEISFQPGDIIQVD--ESQVAEPGWLAG--ELKGKTGWFPANYVEK 55

Third Src Homology 3 domain of SH3 domain containing ring finger 1 (SH3RF1), SH3RF3, and similar domains; SH3RF1 (or POSH) and SH3RF3 (or POSH2) are scaffold proteins that function as E3 ubiquitin-protein ligases. They contain an N-terminal RING finger domain and four SH3 domains. This model represents the third SH3 domain, located in the middle of SH3RF1 and SH3RF3, and similar domains. 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. 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 768020971 283 ALFQYKPQNVDELTLSPGDYIFVDPTQQDeaseGWVIGISQRTGCRGFLPENY 335
Cdd:cd11783    4 ALYPYKPQKPDELELRKGEMYTVTEKCQD----GWFKGTSLRTGQSGVFPGNY 52

First Src homology 3 domain (or SH3A) 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 first SH3 domain (or SH3A) of ITSN1 has been shown to bind many proteins including Sos1, dynamin1/2, CIN85, c-Cbl, PI3K-C2, SHIP2, N-WASP, and CdGAP, 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 768020971 282 RALFQYKPQNVDELTLSPGDYIFVDPTQQDEAseGWVIGisQRTGCRGFLPENYTDR 338
Cdd:cd11987    3 RALYPFEARSHDEITIQPGDIVMVDESQTGEP--GWLGG--ELKGKTGWFPANYAEK 55

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
                 ....*....|....*....|....*....|....*....|....*....|....
gi 768020971 282 RALFQYKPQNVDELTLSPGDYIFVdpTQQDeASEGWVIGISQRtGCRGFLPENY 335
Cdd:cd11763    3 RALYDFDSQPSGELSLRAGEVLTI--TRQD-VGDGWLEGRNSR-GEVGLFPSSY 52

Src Homology 3 domain of SH3 domain-containing protein 21 (SH3D21) and similar proteins; N-terminal SH3 domain of the uncharacterized protein SH3 domain-containing protein 21, and similar uncharacterized domains, it belongs to the CD2AP-like_3 subfamily of proteins. The CD2AP-like_3 subfamily is composed of the third SH3 domain (SH3C) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3C of both proteins have been shown to bind to ubiquitin. 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 768020971 282 RALFQYKPQNVDELTLSPGDYIFVdpTQQDEASEGWVIGisQRTGCRGFLPENY 335
Cdd:cd12142    3 RVLFDYNPVAPDELALKKGDVIEV--ISKETEDEGWWEG--ELNGRRGFFPDNF 52

First Src homology 3 domain (or SH3A) 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 first SH3 domain (or SH3A) of ITSN2 is expected to bind many protein partners, similar to ITSN1 which has been shown to bind Sos1, dynamin1/2, CIN85, c-Cbl, PI3K-C2, SHIP2, N-WASP, and CdGAP, 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 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFVDPTQQDEAseGWVIGISQrtGCRGFLPENYTDR 338
Cdd:cd11988    3 NYRALYPFEARNHDEMSFNAGDIIQVDEKTVGEP--GWLYGSFQ--GNFGWFPCNYVEK 57

Src homology 3 domain of JNK-interacting proteins 1 and 2, and similar domains; JNK-interacting proteins (JIPs) function as scaffolding proteins for c-Jun N-terminal kinase (JNK) signaling pathways. They bind to components of Mitogen-activated protein kinase (MAPK) pathways such as JNK, MKK, and several MAP3Ks such as MLK and DLK. There are four JIPs (JIP1-4); all contain a JNK binding domain. JIP1 and JIP2 also contain SH3 and Phosphotyrosine-binding (PTB) domains. Both are highly expressed in the brain and pancreatic beta-cells. JIP1 functions as an adaptor linking motor to cargo during axonal transport and also is involved in regulating insulin secretion. JIP2 form complexes with fibroblast growth factor homologous factors (FHFs), which facilitates activation of the p38delta MAPK. The SH3 domain of JIP1 homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFVdptqQDEASEGWVIGISQRTGCRGFLPENY 335
Cdd:cd11801    1 THRALHKFIPRHEDEIELDIGDPVYV----EQEADDLWCEGTNLRTGQRGIFPAAY 52

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        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 768020971 282 RALFQYKPQNVDELTLSPGDYIFVdptqQDEASEGWVIGISQrtGCRGFLPENY 335
Cdd:cd11772    3 RALYDYEAQHPDELSFEEGDLLYI----SDKSDPNWWKATCG--GKTGLIPSNY 50

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        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 768020971 282 RALFQYKPQNVDELTLSPGDYIFVdptqQDEASEGWviGISQRTGCRGFLPENY 335
Cdd:cd11824    3 SVLYDYTAQEDDELSISKGDVVAV----IEKGEDGW--WTVERNGQKGLVPGTY 50

Src homology 3 domain of JNK-interacting protein 2; JNK-interacting protein 2 (JIP2) is also called Mitogen-activated protein kinase 8-interacting protein 2 (MAPK8IP2) or Islet-brain-2 (IB2). It is widely expressed in the brain, where it forms complexes with fibroblast growth factor homologous factors (FHFs), which facilitates activation of the p38delta MAPK. JIP2 is enriched in postsynaptic densities and may play a role in motor and cognitive function. In addition to a JNK binding domain, JIP2 also contains SH3 and Phosphotyrosine-binding (PTB) domains. The SH3 domain of the related protein JIP1 homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFVDPTQQDEasegWVIGISQRTGCRGFLPENY 335
Cdd:cd11942    1 THRAVFRFIPRHEDELELDVDDPLLVEAEEDDY----WYRGYNMRTGERGIFPAFY 52

Src homology 3 domain of Cortactin and related proteins; This subfamily includes cortactin, Abp1 (actin-binding protein 1), hematopoietic lineage cell-specific protein 1 (HS1), and similar proteins. These proteins are involved in regulating actin dynamics through direct or indirect interaction with the Arp2/3 complex, which is required to initiate actin polymerization. They all contain at least one C-terminal SH3 domain. Cortactin and HS1 bind Arp2/3 and actin through an N-terminal region that contains an acidic domain and several copies of a repeat domain found in cortactin and HS1. Abp1 binds actin via an N-terminal actin-depolymerizing factor (ADF) homology domain. Yeast Abp1 binds Arp2/3 directly through two acidic domains. Mammalian Abp1 does not directly interact with Arp2/3; instead, it regulates actin dynamics indirectly by interacting with dynamin and WASP family proteins. The C-terminal region of these proteins acts as an adaptor or scaffold that can connect membrane trafficking and signaling proteins that bind the SH3 domain within the actin network. 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 768020971 282 RALFQYKPQNVDELTLSPGDYIfvdpTQQDEASEGWVIGISqRTGCRGFLPENY 335
Cdd:cd11819    3 KALYDYQAAEDNEISFVEGDII----TQIEQIDEGWWLGVN-AKGQKGLFPANY 51

UBA1 domain found in ubiquitin carboxyl-terminal hydrolase UBP5, UBP13 and similar proteins; UBP5, also called deubiquitinating enzyme 5, Isopeptidase T (IsoT), ubiquitin thioesterase 5, or ubiquitin-specific-processing protease 5, is a deubiquitinating enzyme largely responsible for the disassembly of the majority of unanchored polyubiquitin in the cell. Zinc is required for its catalytic activity. UBP5 contains four ubiquitin (Ub)-binding sites including an N-terminal zinc finger (ZnF) domain, a catalytic ubiquitin-specific processing protease (UBP) domain (catalytic C-box and H-box), and two ubiquitin-associated (UBA) domains. ZnF domain binds the proximal ubiquitin. UBP domain forms the active site. UBA domains are involved in binding linear or K48-linked polyubiquitin. UBP13, also called deubiquitinating enzyme 13, Isopeptidase T-3 (isoT3), ubiquitin thioesterase 13, or ubiquitin-specific-processing protease 13, is an ortholog of UBP5. It has similar domain architecture, but functions differently from USP5 in cellular deubiquitination processes. It exhibits a weak deubiquitinating activity preferring to Lys63-linked polyubiquitin in a non-activation manner. Moreover, the zinc finger (ZnF) domain of USP13 cannot bind to Ub. Its tandem UBA domains can bind with different types of diUb but preferentially with K63-linked.USP13 can also regulate the protein level of CD3delta in cells via its UBA domains. This model corresponds to the UBA1 domain.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|...
gi 768020971  22 PSLLEPLLAMGFPVHTALKALAATGRKTAEEALAWLHDHCNDP 64
Cdd:cd14294    1 EAVVSQLAEMGFPLEACRKAVYHTNNSGLEAAMNWIMEHMDDP 43

Src Homology 3 domain of Insulin Receptor tyrosine kinase Substrate p53, Brain-specific Angiogenesis Inhibitor 1-Associated Protein 2 (BAIAP2)-Like proteins, and similar proteins; Proteins in this family include IRSp53, BAIAP2L1, BAIAP2L2, and similar proteins. They all contain an Inverse-Bin/Amphiphysin/Rvs (I-BAR) or IMD domain in addition to the SH3 domain. IRSp53, also known as BAIAP2, is a scaffolding protein that takes part in many signaling pathways including Cdc42-induced filopodia formation, Rac-mediated lamellipodia extension, and spine morphogenesis. IRSp53 exists as multiple splicing variants that differ mainly at the C-termini. BAIAP2L1, also called IRTKS (Insulin Receptor Tyrosine Kinase Substrate), serves as a substrate for the insulin receptor and binds the small GTPase Rac. It plays a role in regulating the actin cytoskeleton and colocalizes with F-actin, cortactin, VASP, and vinculin. IRSp53 and IRTKS also mediate the recruitment of effector proteins Tir and EspFu, which regulate host cell actin reorganization, to bacterial attachment sites. BAIAP2L2 co-localizes with clathrin plaques but its function has not been determined. The SH3 domains of IRSp53 and IRTKS have been shown to bind the proline-rich C-terminus of EspFu. 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 768020971 279 QTLRALFQYKPQNVDELTLSPGDYIFVdptQQDEASEGWVIGISQRTGCRGFLPENYT 336
Cdd:cd11779    1 PRVKALYPHAAGGETQLSFEEGDVITL---LGPEPRDGWHYGENERSGRRGWFPIAYT 55

Src homology 3 domain of JNK-interacting protein 1; JNK-interacting protein 1 (JIP1) is also called Islet-brain 1 (IB1) or Mitogen-activated protein kinase 8-interacting protein 1 (MAPK8IP1). It is highly expressed in neurons, where it functions as an adaptor linking motor to cargo during axonal transport. It also affects microtubule dynamics in neurons. JIP1 is also found in pancreatic beta-cells, where it is involved in regulating insulin secretion. In addition to a JNK binding domain, JIP1 also contains SH3 and Phosphotyrosine-binding (PTB) domains. Its SH3 domain homodimerizes at the interface usually involved in proline-rich ligand recognition, despite the lack of this motif in the domain itself. 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 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFVDPTQQDEasegWVIGISQRTGCRGFLPENY 335
Cdd:cd11943    1 THRAVFRFVPRHPDELELEVDDPLLVEVQAEDY----WYEAYNMRTGARGIFPAYY 52

Src homology 3 domain of an unknown subfamily of proteins with similarity to 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 768020971 279 QTLRALFQYKPQNVDELTLSPGDYIFvdpTQQDEASEGWVIGISQRtGCRGFLPENY 335
Cdd:cd11999    2 VRVRAVYDYTGQEPDELSFKAGEELL---KVEDEDEQGWCKGVTDG-GAVGLYPANY 54

C-terminal Src homology 3 domain of SH3 and cysteine-rich domain-containing protein 2 (Stac2); Stac proteins are putative adaptor proteins that contain a cysteine-rich C1 domain and one or two SH3 domains at the C-terminus. There are three mammalian members (Stac1, Stac2, and Stac3) of this family. Stac2 contains a single SH3 domain at the C-terminus unlike Stac1 and Stac3, which contain two C-terminal SH3 domains. Stac1 and Stac2 have been found to be expressed differently in mature dorsal root ganglia (DRG) neurons. Stac1 is mainly expressed in peptidergic neurons while Stac2 is found in a subset of nonpeptidergic and all trkB+ neurons. 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 768020971 283 ALFQYKPQNVDELTLSPGDYIFVdptqQDEASEGWVIGisqRTGCR-GFLPENYTDR 338
Cdd:cd11985    4 ALYKFLPQENNDLPLQPGDRVMV----VDDSNEDWWKG---KSGDRvGFFPANFVQR 53

First Src Homology 3 domain of FCH and double SH3 domains proteins; This group is composed of FCH and double SH3 domains protein 1 (FCHSD1) and FCHSD2. These proteins have a common domain structure consisting of an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), two SH3, and C-terminal proline-rich domains. They have only been characterized in silico and their functions remain unknown. This group also includes the insect protein, nervous wreck, which acts as a regulator of synaptic growth signaling. 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 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFVdptQQDEASEGWVIGISQRtGCRGFLPENYTD 337
Cdd:cd11761    3 TCKVLYSYEAQRPDELTITEGEELEV---IEDGDGDGWVKARNKS-GEVGYVPENYLQ 56

First Src Homology 3 domain (SH3A) of CD2-associated protein and similar proteins; This subfamily is composed of the first SH3 domain (SH3A) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3A of both proteins bind to an atypical PXXXPR motif at the C-terminus of Cbl and the cytoplasmic domain of the cell adhesion protein CD2. CIN85 SH3A binds to internal proline-rich motifs within the proline-rich region; this intramolecular interaction serves as a regulatory mechanism to keep CIN85 in a closed conformation, preventing the recruitment of other proteins. CIN85 SH3A has also been shown to bind ubiquitin. 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 768020971 280 TLRALFQYKPQNVDELTLSPGDyIFVDPTQQDeasEGWVIGisQRTGCRGFLPENY 335
Cdd:cd11873    1 EVIVEFDYDAEEPDELTLKVGD-IITNVKKME---EGWWEG--TLNGKRGMFPDNF 50

Src homology 3 domain of Myosins Ie, If, and similar proteins; Myosins Ie (MyoIe) and If (MyoIf) are nonmuscle, unconventional, long tailed, class I myosins containing an N-terminal motor domain and a myosin tail with TH1, TH2, and SH3 domains. MyoIe interacts with the endocytic proteins, dynamin and synaptojanin-1, through its SH3 domain; it may play a role in clathrin-dependent endocytosis. In the kidney, MyoIe is critical for podocyte function and normal glomerular filtration. Mutations in MyoIe is associated with focal segmental glomerulosclerosis, a disease characterized by massive proteinuria and progression to end-stage kidney disease. MyoIf is predominantly expressed in the immune system; it plays a role in immune cell motility and innate immunity. Mutations in MyoIf may be associated with the loss of hearing. The MyoIf gene has also been found to be fused to the MLL (Mixed lineage leukemia) gene in infant acute myeloid leukemias (AML). 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 768020971 282 RALFQYKPQNVDELTLSPGDYIfvDPTQQDEAseGWVIGisQRTGCRGFLPENYTDR 338
Cdd:cd11827    3 KALYAYDAQDTDELSFNEGDII--EILKEDPS--GWWTG--RLRGKEGLFPGNYVEK 53

Src Homology 3 domain of Saccharomyces cerevisiae Nap1-binding protein 2 and similar fungal proteins; This subfamily includes Saccharomyces cerevisiae Nbp2 (Nucleosome assembly protein 1 (Nap1)-binding protein 2), Schizosaccharomyces pombe Skb5, and similar proteins. Nbp2 interacts with Nap1, which is essential for maintaining proper nucleosome structures in transcription and replication. It is also the binding partner of the yeast type II protein phosphatase Ptc1p and serves as a scaffolding protein that brings seven kinases in close contact to Ptc1p. Nbp2 plays a role many cell processes including organelle inheritance, mating hormone response, cell wall stress, mitotic cell growth at elevated temperatures, and high osmolarity. Skb5 interacts with the p21-activated kinase (PAK) homolog Shk1, which is critical for fission yeast cell viability. Skb5 activates Shk1 and plays a role in regulating cell morphology and growth under hypertonic conditions. Nbp2 and Skb5 contain an 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 768020971 283 ALFQYKPQNVDELTLSPGDYIFVdptqQDEASEGWVIGISQRTGCRGFLPENY 335
Cdd:cd11865    4 ALYDFEPEHDNELGFAEGQILFI----LYKHGQGWLIAEDESGGKTGLVPEEF 52

Third Src Homology 3 domain of SH3 domain containing ring finger 1, an E3 ubiquitin-protein ligase; SH3RF1 is also called POSH (Plenty of SH3s) or SH3MD2 (SH3 multiple domains protein 2). It is a scaffold protein that acts as an E3 ubiquitin-protein ligase. It 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. SH3RF1 also enhances the ubiquitination of ROMK1 potassium channel resulting in its increased endocytosis. It contains an N-terminal RING finger domain and four SH3 domains. This model represents the third SH3 domain, located in the middle, 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.

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                 ....*....|....*....|....*....|....*....|....*....|...
gi 768020971 283 ALFQYKPQNVDELTLSPGDYIFVDPTQQDeaseGWVIGISQRTGCRGFLPENY 335
Cdd:cd11926    4 AIYPYTPRKEDELELRKGEMFLVFERCQD----GWFKGTSMHTSKIGVFPGNY 52

Src Homology 3 domain of Amphiphysin I; Amphiphysins function primarily in endocytosis and other membrane remodeling events. They exist in several isoforms and mammals possess two amphiphysin proteins from distinct genes. Amphiphysin I proteins, enriched in the brain and nervous system, contain domains that bind clathrin, Adaptor Protein complex 2 (AP2), dynamin, and synaptojanin. They function in synaptic vesicle endocytosis. Human autoantibodies to amphiphysin I hinder GABAergic signaling and contribute to the pathogenesis of paraneoplastic stiff-person syndrome. Amphiphysins contain an N-terminal BAR domain with an additional N-terminal amphipathic helix (an N-BAR), a variable central domain, and a C-terminal SH3 domain. The SH3 domain of amphiphysins bind proline-rich motifs present in binding partners such as dynamin, synaptojanin, and nsP3. It also belongs to a subset of SH3 domains that bind ubiquitin in a site that overlaps with the peptide binding site. 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        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 768020971 284 LFQYKPQNVDELTLSPGDYIFVDPTQQDEASE-GWVIGISQR--------TGCRGFLPENYTDR 338
Cdd:cd12140    8 LHDFEAANSDELELKRGDIVLVVPSETAADQDaGWLTGVKESdwlqyrdaSAYKGLFPENFTRR 71

Src homology 3 domain of Protein kinase C and Casein kinase Substrate in Neurons 1 (PACSIN1) and PACSIN 2; PACSIN 1 or Syndapin I (Synaptic dynamin-associated protein I) is expressed specifically in the brain and is localized in neurites and synaptic boutons. It binds the brain-specific proteins dynamin I, synaptojanin, synapsin I, and neural Wiskott-Aldrich syndrome protein (nWASP), and functions as a link between the cytoskeletal machinery and synaptic vesicle endocytosis. PACSIN 1 interacts with huntingtin and may be implicated in the neuropathology of Huntington's disease. PACSIN 2 or Syndapin II is expressed ubiquitously and is involved in the regulation of tubulin polymerization. It associates with Golgi membranes and forms a complex with dynamin II which is crucial in promoting vesicle formation from the trans-Golgi network. PACSINs act as regulators of cytoskeletal and membrane dynamics. 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.

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                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 768020971 281 LRALFQYKPQNVDELTLSPGDYIfvdPTQQDEASEGWVIGiSQRTGCRGFLPENYTD 337
Cdd:cd11998    3 VRALYDYDGQEQDELSFKAGDEL---TKLEDEDEQGWCKG-RLDSGQVGLYPANYVE 55

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.

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                 ....*....|....*....|....*....|....*....|....*....|....
gi 768020971 282 RALFQYKPQNVDELTLSPGDyIFVDPTQQDEasEGWVIGisQRTGCRGFLPENY 335
Cdd:cd11843    3 RALYDYEGQESDELSFKAGD-ILTKLEEEDE--QGWCKG--RLDGRVGLYPANY 51

Src Homology 3 domain of the p85beta regulatory subunit of Class IA Phosphatidylinositol 3-kinases; Class I PI3Ks convert PtdIns(4,5)P2 to the critical second messenger PtdIns(3,4,5)P3. They are heterodimers and exist in multiple isoforms consisting of one catalytic subunit (out of four isoforms) and one of several regulatory subunits. Class IA PI3Ks associate with the p85 regulatory subunit family, which contains SH3, RhoGAP, and SH2 domains. The p85 subunits recruit the PI3K p110 catalytic subunit to the membrane, where p110 phosphorylates inositol lipids. Vertebrates harbor two p85 isoforms, called alpha and beta. In addition to regulating the p110 subunit, p85beta binds CD28 and may be involved in the activation and differentiation of antigen-stimulated T cells. 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 768020971 282 RALFQYKPQNVDELTLSPGDYIFVDPT-----------QQDEASEGWVIGISQRTGCRGFLPENYTD 337
Cdd:cd11909    4 RALYPYRKEREEDIDLLPGDVLTVSRAalqalgvkeggEQCPQSIGWILGLNERTKQRGDFPGTYVE 70

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 768020971 280 TLRALFQYKPQNVDELTLSPGDYIFV-DPTQQDeasegWVIGISQRTGCRGFLPENY 335
Cdd:cd11845    1 IYVALYDYEARTDDDLSFKKGDRLQIlDDSDGD-----WWLARHLSTGKEGYIPSNY 52