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        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 2077087849 241 QTLRALFQYKPQNIDELMINAGDFIYVNPTQQSEVSEGWVIGTSHQSGCRGFLPENYTER 300
Cdd:cd11937     1 QTLRALFQYKPQNIDELMLSPGDYIFVDPTQQSEASEGWVIGISHRTGCRGFLPENYTER 60

UBA domain found in ubiquitin-associated and SH3 domain-containing protein A (UBS3A) and similar proteins; UBS3A, also called Cbl-interacting protein 4 (CLIP4), suppressor of T-cell receptor signaling 2 (Sts-2), or T-cell ubiquitin ligand 1 (TULA-1), is a lymphoid protein only detected in thymus, spleen, and bone marrow. UBS3A exhibits extremely low phosphatase activity, but is capable of promoting T-cell apoptosis independent of either T cell receptor (TCR)/CD3-mediated signaling or caspase activity. It functions as a negative regulator of TCR signaling. UBS3A can also inhibit HIV-1 biogenesis through the binding of ATP-binding cassette protein family E member 1 (ABCE-1), a host factor of HIV-1 assembly. Moreover, UBS3A acts as the Cbl- and ubiquitin-interacting protein that can inhibit endocytosis and downregulation of ligand-activated epidermal growth factor receptor (EGFR) by impairing Cbl-induced ubiquitination, as well as inhibit clathrin-dependent endocytosis in general. This family also includes Arabidopsis thaliana ubiquitin carboxyl-terminal hydrolase 14 (atUBP14) and some uncharacterized AAA-type ATPase-like proteins found in plants.

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 2077087849  25 LESLLAKGFPAHIAQKALVATGQKSIEDAAKWLHSHC 61
Cdd:cd14300     1 LETLLAMGFPEDVARKALKATGGKSIEKATDWLLSHC 37

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 2077087849 241 QTLRALFQYKPQNIDELMINAGDFIYVNPTQQSEVSEGWVIGTSHQSGCRGFLPENYTER 300
Cdd:cd11937     1 QTLRALFQYKPQNIDELMLSPGDYIFVDPTQQSEASEGWVIGISHRTGCRGFLPENYTER 60

UBA domain found in ubiquitin-associated and SH3 domain-containing protein A (UBS3A) and similar proteins; UBS3A, also called Cbl-interacting protein 4 (CLIP4), suppressor of T-cell receptor signaling 2 (Sts-2), or T-cell ubiquitin ligand 1 (TULA-1), is a lymphoid protein only detected in thymus, spleen, and bone marrow. UBS3A exhibits extremely low phosphatase activity, but is capable of promoting T-cell apoptosis independent of either T cell receptor (TCR)/CD3-mediated signaling or caspase activity. It functions as a negative regulator of TCR signaling. UBS3A can also inhibit HIV-1 biogenesis through the binding of ATP-binding cassette protein family E member 1 (ABCE-1), a host factor of HIV-1 assembly. Moreover, UBS3A acts as the Cbl- and ubiquitin-interacting protein that can inhibit endocytosis and downregulation of ligand-activated epidermal growth factor receptor (EGFR) by impairing Cbl-induced ubiquitination, as well as inhibit clathrin-dependent endocytosis in general. This family also includes Arabidopsis thaliana ubiquitin carboxyl-terminal hydrolase 14 (atUBP14) and some uncharacterized AAA-type ATPase-like proteins found in plants.

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 2077087849  25 LESLLAKGFPAHIAQKALVATGQKSIEDAAKWLHSHC 61
Cdd:cd14300     1 LETLLAMGFPEDVARKALKATGGKSIEKATDWLLSHC 37

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 2077087849 364 VLVMRHGERVDQVFGKSwlqqcltadgkyyradlnfpstlpkrkdsvkHFEHDPPLSSCGVFQSRLIGEALLDQEVTVSY 443
Cdd:cd07067     2 LYLVRHGESEWNAEGRF-------------------------------QGWTDVPLTEKGREQARALGKRLKELGIKFDR 50

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2077087849 444 MYSSPALRCIQTAQHVLQGLkldQKVKIRVEPGLFEwtkweasrvipnfmtltelteasynidtsyrgiiplsslvpses 523
Cdd:cd07067    51 IYSSPLKRAIQTAEIILEEL---PGLPVEVDPRLRE-------------------------------------------- 83

                         170       180       190       200       210
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2077087849 524 yeeyvSRSSAVIKEIVTACPSKgVILIVGHGSSLASFTRPLIGLPARDSSDF 575
Cdd:cd07067    84 -----ARVLPALEELIAPHDGK-NVLIVSHGGVLRALLAYLLGLSDEDILRL 129

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        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2077087849  415 HDPPLSSCGVFQSRLIGEALLDQ-EVTVSYMYSSPALRCIQTAQHVLQGLKLDQKVKIrvEPGLFE-WTKWEASRVIPNF 492
Cdd:smart00855  22 TDVPLTELGRAQAEALGRLLASLlLPRFDVVYSSPLKRARQTAEALAIALGLPGLRER--DFGAWEgLTWDEIAAKYPEE 99

                           90       100       110       120       130       140
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 2077087849  493 MTLTELTEASYNIDTSYRGiiplsslvpsESYEEYVSRSSAVIKEIV-TACPSKGVILIVGHGSSLASF 560
Cdd:smart00855 100 YLAAWRDPYDPAPPAPPGG----------ESLADLVERVEPALDELIaTADASGQNVLIVSHGGVIRAL 158

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 2077087849  241 QTLRALFQYKPQNIDELMINAGDFIYVnptqQSEVSEGWVIGTSHqSGCRGFLPENYTE 299
Cdd:smart00326   3 PQVRALYDYTAQDPDELSFKKGDIITV----LEKSDDGWWKGRLG-RGKEGLFPSNYVE 56

phosphoglycerate mutase like-protein; Provisional

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 2077087849 415 HDPPLSSCGVFQSRLIGEALLDQEVTVSYMYSSPALRCIQTAQHVLQGL 463
Cdd:PTZ00123   11 TDVPLSEKGVQEAREAGKLLKEKGFRFDVVYTSVLKRAIKTAWIVLEEL 59

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 2077087849 241 QTLRALFQYKPQNIDELMINAGDFIYVNPTQQSEVSEGWVIGTSHQSGCRGFLPENYTER 300
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 2077087849 240 YQTLRALFQYKPQNIDELMINAGDFIYVNPTQQSEVSEGWVIGTSHQSGCRGFLPENYTERA 301
Cdd:cd11936     1 HETLQVIYPYTPQNDDELELVPGDYIFMSPMEQTSTSEGWIYGTSLTTGCSGLLPENYITKA 62

UBA domain found in ubiquitin-associated and SH3 domain-containing protein A (UBS3A) and similar proteins; UBS3A, also called Cbl-interacting protein 4 (CLIP4), suppressor of T-cell receptor signaling 2 (Sts-2), or T-cell ubiquitin ligand 1 (TULA-1), is a lymphoid protein only detected in thymus, spleen, and bone marrow. UBS3A exhibits extremely low phosphatase activity, but is capable of promoting T-cell apoptosis independent of either T cell receptor (TCR)/CD3-mediated signaling or caspase activity. It functions as a negative regulator of TCR signaling. UBS3A can also inhibit HIV-1 biogenesis through the binding of ATP-binding cassette protein family E member 1 (ABCE-1), a host factor of HIV-1 assembly. Moreover, UBS3A acts as the Cbl- and ubiquitin-interacting protein that can inhibit endocytosis and downregulation of ligand-activated epidermal growth factor receptor (EGFR) by impairing Cbl-induced ubiquitination, as well as inhibit clathrin-dependent endocytosis in general. This family also includes Arabidopsis thaliana ubiquitin carboxyl-terminal hydrolase 14 (atUBP14) and some uncharacterized AAA-type ATPase-like proteins found in plants.

                          10        20        30
                  ....*....|....*....|....*....|....*..
gi 2077087849  25 LESLLAKGFPAHIAQKALVATGQKSIEDAAKWLHSHC 61
Cdd:cd14300     1 LETLLAMGFPEDVARKALKATGGKSIEKATDWLLSHC 37

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 2077087849 364 VLVMRHGERVDQVFGKSwlqqcltadgkyyradlnfpstlpkrkdsvkHFEHDPPLSSCGVFQSRLIGEALLDQEVTVSY 443
Cdd:cd07067     2 LYLVRHGESEWNAEGRF-------------------------------QGWTDVPLTEKGREQARALGKRLKELGIKFDR 50

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2077087849 444 MYSSPALRCIQTAQHVLQGLkldQKVKIRVEPGLFEwtkweasrvipnfmtltelteasynidtsyrgiiplsslvpses 523
Cdd:cd07067    51 IYSSPLKRAIQTAEIILEEL---PGLPVEVDPRLRE-------------------------------------------- 83

                         170       180       190       200       210
                  ....*....|....*....|....*....|....*....|....*....|..
gi 2077087849 524 yeeyvSRSSAVIKEIVTACPSKgVILIVGHGSSLASFTRPLIGLPARDSSDF 575
Cdd:cd07067    84 -----ARVLPALEELIAPHDGK-NVLIVSHGGVLRALLAYLLGLSDEDILRL 129

alpha-ribazole phosphatase; Members of this protein family include the known CobC protein of Salmonella and Eschichia coli species, and homologous proteins found in cobalamin biosynthesis regions in other bacteria. This protein is alpha-ribazole phosphatase (EC 3.1.3.73) and, like many phosphatases, can be closely related in sequence to other phosphatases with different functions. Close homologs excluded from this model include proteins with duplications, so this model is built in -g mode to suppress hits to those proteins. [Biosynthesis of cofactors, prosthetic groups, and carriers, Heme, porphyrin, and cobalamin]

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2077087849 415 HDPPLSSCGVFQSRLIGEALLDqeVTVSYMYSSPALRCIQTAQHVLQGLKLdqkvKIRVEPGLFE--WTKWEAsrvipnf 492
Cdd:TIGR03162  20 TDVPLAESGEEQAAALREKLAD--VPFDAVYSSPLSRCRELAEILAERRGL----PIIKDDRLREmdFGDWEG------- 86

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2077087849 493 MTLTELTEASYNIDTSYRGiiPLSSLVPS-ESYEEYVSRSSAVIKEIVTAcPSKGVILIVGHGSSLASFTRPLIGLPA 569
Cdd:TIGR03162  87 RSWDEIPEAYPELDAWAAD--WQHARPPGgESFADFYQRVSEFLEELLKA-HEGDNVLIVTHGGVIRALLAHLLGLPL 161

Third (or C-terminal) 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 third 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.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 2077087849 244 RALFQYKPQNIDELMINAGDFIYVnptqQSEVSEGWVIGTSHQSGCRGFLPENYTER 300
Cdd:cd11780     3 RALYSYTPQNEDELELREGDIVYV----MEKCDDGWFVGTSERTGLFGTFPGNYVAR 55

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 2077087849 242 TLRALFQYKPQNIDELMINAGDFIYVNPTQ-QSEVSEGWVIGTSHQSGCRGFLPENYTER 300
Cdd:cd11790     4 KVRATHDYTAEDTDELTFEKGDVILVIPFDdPEEQDEGWLMGVKESTGCRGVFPENFTER 63

C-terminal Src Homology 3 domain of Nebulette and LIM-nebulette (or Lasp2); Nebulette is a cardiac-specific protein that localizes to the Z-disc. It interacts with tropomyosin and is important in stabilizing actin thin filaments in cardiac muscles. Polymorphisms in the nebulette gene are associated with dilated cardiomyopathy, with some mutations resulting in severe heart failure. Nebulette is a 107kD protein that contains an N-terminal acidic region, multiple nebulin repeats, and a C-terminal SH3 domain. LIM-nebulette, also called Lasp2 (LIM and SH3 domain protein 2), is an alternatively spliced variant of nebulette. Although it shares a gene with nebulette, Lasp2 is not transcribed from a muscle-specific promoter, giving rise to its multiple tissue expression pattern with highest amounts in the brain. It can crosslink actin filaments and it affects cell spreading. Lasp2 is a 34kD protein containing an N-terminal LIM domain, three 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        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2077087849 241 QTLRALFQYKPQNIDELMINAGDFIY-VNPtqqseVSEGWVIGTSHQSGCRGFLPENYTERAN 302
Cdd:cd11935     1 RTYRAMYDYSAQDEDEVSFRDGDYIVnVQP-----IDEGWMYGTVQRTGRTGMLPANYIEFVN 58

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 2077087849 241 QTLRALFQYKPQNIDELMINAGDFIYVnpTQQSEvsEGWVIGTSHQSGCRGFLPENY 297
Cdd:cd11918     2 TPYKAVYQYRPQNEDELELREGDRVDV--MQQCD--DGWFVGVSRRTQKFGTFPGNY 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 2077087849  22 SALLESLLAKGFPAHIAQKALVATGQKSIEDAAKWLHSHCNDPSLD 67
Cdd:cd14385     2 AEALAQLLGMGFPEVRCKKALLATGNSDAEAAMNWLFEHMDDPDID 47

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 2077087849 244 RALFQYKPQNIDELMINAGDFIYVnptqQSEVSEGWVIGTSHqSGCRGFLPENY 297
Cdd:cd00174     3 RALYDYEAQDDDELSFKKGDIITV----LEKDDDGWWEGELN-GGREGLFPANY 51

Second Src Homology 3 domain (SH3B) of CD2-associated protein; CD2AP, also called CMS (Cas ligand with Multiple SH3 domains) or METS1 (Mesenchyme-to-Epithelium Transition protein with SH3 domains), is a cytosolic adaptor protein that plays a role in regulating the cytoskeleton. It is critical in cell-to-cell union necessary for kidney function. It also stabilizes the contact between a T cell and antigen-presenting cells. It is primarily expressed in podocytes at the cytoplasmic face of the slit diaphragm and serves as a linker anchoring podocin and nephrin to the actin cytoskeleton. CD2AP contains three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP to bind various protein partners and assemble complexes that have been implicated in many different functions. This alignment model represents the second SH3 domain (SH3B) of CD2AP. SH3B binds to c-Cbl in a site (TPSSRPLR is the core binding motif) distinct from the c-Cbl/SH3A 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
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2077087849 244 RALFQYKPQNIDELMINAGDFIYVNptqqSEVSEGWVIGTshQSGCRGFLPENYTE 299
Cdd:cd12054     4 KVLFEYVPQNEDELELKVGDIIDIN----EEVEEGWWSGT--LNGKSGLFPSNFVK 53

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 2077087849 242 TLRALFQYKPQNIDELMINAGDFIYVnptqQSEVSEGWVIGTSHQSGCRGFLPENYTE 299
Cdd:cd11916     3 SYQALYSYAPQNDDELELRDGDIVDV----MEKCDDGWFVGTSRRTKQFGTFPGNYVK 56

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 2077087849 242 TLRALFQYKPQNIDELMINAGDFIyVNPTqqsEVSEGWVIGTSHQSGCRGFLPENYTE 299
Cdd:cd11789     1 RYRAMYDYAAADDDEVSFQEGDVI-INVE---IIDDGWMEGTVQRTGQSGMLPANYVE 54

UBA domain found in UBX domain-containing protein 1 (UBXN1) and similar proteins; UBXN1, also called SAPK substrate protein 1 (SAKS1) or UBA/UBX 33.3 kDa protein, is a widely expressed protein containing an N-terminal ubiquitin-associated (UBA) domain, a coiled-coil region, and a C-terminal ubiquitin-like (UBX) domain. It binds polyubiquitin and valosin-containing protein (VCP), and has been identified as a substrate for stress-activated protein kinases (SAPKs). Moreover, UBXN1 specifically binds to Homer2b. It may also interact with ubiquitin (Ub) and may be involved in the Ub-proteasome proteolytic pathways. In addition, UBXN1 can associate with autoubiquitinated BRCA1 tumor suppressor and inhibit its enzymatic function through its UBA domain.

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 2077087849  25 LESLLAKGFPAHIAQKALVATGQKSIEDAAKWLHSHCND 63
Cdd:cd14302     3 LQTLIEMGFSRNRAEKALAKTGNQGVEAAMEWLLAHEDD 41

Third (or C-terminal) Src Homology 3 domain of Sorbin and SH3 domain containing 2 (Sorbs2), also called Arg-binding protein 2 (ArgBP2); Sorbs2 or ArgBP2 is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. It regulates actin-dependent processes including cell adhesion, morphology, and migration. It is expressed in many tissues and is abundant in the heart. Like vinexin, it is found in focal adhesion where it interacts with vinculin and afadin. It also localizes in epithelial cell stress fibers and in cardiac muscle cell Z-discs. Sorbs2 has been implicated to play roles in the signaling of c-Arg, Akt, and Pyk2. Other interaction partners of Sorbs2 include c-Abl, flotillin, spectrin, dynamin 1/2, synaptojanin, PTP-PEST, 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        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|
gi 2077087849 241 QTLRALFQYKPQNIDELMINAGDFIYVnptqQSEVSEGWVIGTSHQSGCRGFLPENYTER 300
Cdd:cd11917     5 EPFQALYNYMPRNEDELELREGDVIDV----MEKCDDGWFVGTSRRTKFFGTFPGNYVKR 60

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.

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                  ....*....|....*....|....*....|....*....|....*..
gi 2077087849  21 PSALLESLLAKGFPAHIAQKALVATGQKSIEDAAKWLHSHCNDPSLD 67
Cdd:cd14290     3 NADLLKELEAMGFPRARAVRALHHTGNTSVEAAVNWIVEHENDPDID 49

Third Src Homology 3 domain of SH3 domain containing ring finger 3, an E3 ubiquitin-protein ligase; SH3RF3 is also called POSH2 (Plenty of SH3s 2) or SH3MD4 (SH3 multiple domains protein 4). It is a scaffold protein with E3 ubiquitin-protein ligase activity. It was identified in the screen for interacting partners of p21-activated kinase 2 (PAK2). It may play a role in regulating JNK mediated apoptosis in certain conditions. It also interacts with GTP-loaded Rac1. SH3RF3 is highly homologous to SH3RF1; it also contains an N-terminal RING finger domain and four SH3 domains. This model represents the third SH3 domain, located in the middle, of SH3RF3. 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 2077087849 245 ALFQYKPQNIDELMINAGDFIYVNPTQQsevsEGWVIGTSHQSGCRGFLPENY 297
Cdd:cd11925     5 ALYAYKPQKNDELELRKGEMYRVIEKCQ----DGWFKGTSLRTGVSGVFPGNY 53

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.

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                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2077087849 244 RALFQYKPQNIDELMINAGDFIYVnpTQQSEVSEGWVIGtsHQSGCRGFLPENYTE 299
Cdd:cd12142     3 RVLFDYNPVAPDELALKKGDVIEV--ISKETEDEGWWEG--ELNGRRGFFPDNFVM 54

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.

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                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2077087849 244 RALFQYKPQNIDELMINAGDFIYVnpTQQSEvsEGWviGTSHQSGCRGFLPENYTE 299
Cdd:cd11824     3 SVLYDYTAQEDDELSISKGDVVAV--IEKGE--DGW--WTVERNGQKGLVPGTYLE 52

UBA2 domain found in Arabidopsis thaliana ubiquitin carboxyl-terminal hydrolase 14 (atUBP14) and similar proteins; atUBP14, also called deubiquitinating enzyme 14, TITAN-6 protein, ubiquitin thioesterase 14, or ubiquitin-specific-processing protease 14, is related to the isopeptidase T class of deubiquitinating enzymes that recycle polyubiquitin chains following protein degradation. atUBP14 is essential for early plant development. It can disassemble multi-ubiquitin chains linked internally via epsilon-amino isopeptide bonds using Lys48 and can process some, but not all, translational fusions of ubiquitin linked via alpha-amino peptide bonds. atUBP14 contains two ubiquitin-association (UBA) domains. This model corresponds to the UBA2 domain which show a high level of sequence similarity with mammalian ubiquitin-associated and SH3 domain-containing protein A (UBS3A).

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                  ....*....|....*....|....*....|....*..
gi 2077087849  24 LLESLLAKGFPAHIAQKALVATGQKsIEDAAKWLHSH 60
Cdd:cd14388     2 SVDTLVSFGFAADVARKALKATGGD-IERAAEWIFNN 37

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.

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                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 2077087849 244 RALFQYKPQNIDELMINAGDFIYVNPTQQSEvsEGWVIGtsHQSGCRGFLPENYTER 300
Cdd:cd11987     3 RALYPFEARSHDEITIQPGDIVMVDESQTGE--PGWLGG--ELKGKTGWFPANYAEK 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.

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                  ....*....|....*....|....*....|....*....|....*....|...
gi 2077087849 245 ALFQYKPQNIDELMINAGDFIYVNPTQQsevsEGWVIGTSHQSGCRGFLPENY 297
Cdd:cd11783     4 ALYPYKPQKPDELELRKGEMYTVTEKCQ----DGWFKGTSLRTGQSGVFPGNY 52

Src Homology 3 domain of Sdc25/Cdc25 guanine nucleotide exchange factors; This subfamily is composed of the Saccharomyces cerevisiae guanine nucleotide exchange factors (GEFs) Sdc25 and Cdc25, and similar proteins. These GEFs regulate Ras by stimulating the GDP/GTP exchange on Ras. Cdc25 is involved in the Ras/PKA pathway that plays an important role in the regulation of metabolism, stress responses, and proliferation, depending on available nutrients and conditions. Proteins in this subfamily contain an N-terminal SH3 domain as well as REM (Ras exchanger motif) and RasGEF domains at the C-terminus. 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 2077087849 242 TLRALFQYKPQNIDELMINAGDFIYVNPTQQSevseGW---VIGTSHQSGCRGFLPENY 297
Cdd:cd11883     1 VVVALYDFTPKSKNQLSFKAGDIIYVLNKDPS----GWwdgVIISSSGKVKRGWFPSNY 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.

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                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 2077087849 244 RALFQYKPQNIDELMINAGDFIYVnpTQQsEVSEGWVIGTSHQsGCRGFLPENYTE 299
Cdd:cd11763     3 RALYDFDSQPSGELSLRAGEVLTI--TRQ-DVGDGWLEGRNSR-GEVGLFPSSYVE 54

Src Homology 3 domain of Pak Interactive eXchange factors; PIX proteins are Rho guanine nucleotide exchange factors (GEFs), which activate small GTPases by exchanging bound GDP for free GTP. They act as GEFs for both Cdc42 and Rac 1, and have been implicated in cell motility, adhesion, neurite outgrowth, and cell polarity. Vertebrates contain two proteins from the PIX subfamily, alpha-PIX and beta-PIX. Alpha-PIX, also called ARHGEF6, is localized in dendritic spines where it regulates spine morphogenesis. Mutations in the ARHGEF6 gene cause X-linked intellectual disability in humans. Beta-PIX play roles in regulating neuroendocrine exocytosis, focal adhesion maturation, cell migration, synaptic vesicle localization, and insulin secretion. PIX proteins contain an N-terminal SH3 domain followed by RhoGEF (also called Dbl-homologous or DH) and Pleckstrin Homology (PH) domains, and a C-terminal leucine-zipper domain for dimerization. The SH3 domain of PIX binds to an atypical PxxxPR motif in p21-activated kinases (PAKs) with high affinity. The binding of PAKs to PIX facilitate the localization of PAKs to focal complexes and also localizes PAKs to PIX targets Cdc43 and Rac, leading to the activation of PAKs. 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 2077087849 244 RALFQYKPQNIDELMINAGDFIYVnpTQQseVSEGWVIGTshQSGCRGFLPENYTE 299
Cdd:cd11877     3 RAKFNFEGTNEDELSFDKGDIITV--TQV--VEGGWWEGT--LNGKTGWFPSNYVK 52

C-terminal (Fourth) 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 fourth SH3 domain, located at the C-terminus 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 2077087849 244 RALFQYKPQNIDELMINAGDFIYVNPTQQsevsEGWVIGTSHQSGCRGFLPENYTE 299
Cdd:cd11785     3 RVIVPYPPQSEAELELKEGDIVFVHKKRE----DGWFKGTLQRTGKTGLFPGSFVE 54

Src homology 3 domain of the Rho guanine nucleotide exchange factors ARHGEF5 and ARHGEF19; ARHGEF5, also called ephexin-3 or TIM (Transforming immortalized mammary oncogene), is a potent activator of RhoA and it plays roles in regulating cell shape, adhesion, and migration. It binds to the SH3 domain of Src and is involved in regulating Src-induced podosome formation. ARHGEF19, also called ephexin-2 or WGEF (weak-similarity GEF), is highly expressed in the intestine, liver, heart and kidney. It activates RhoA, Cdc42, and Rac 1, and has been shown to activate RhoA in the Wnt-PCP (planar cell polarity) pathway. It is involved in the regulation of cell polarity and cytoskeletal reorganization. ARHGEF5 and ARHGEF19 contain RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), and SH3 domains. The SH3 domains of ARHGEFs play an autoinhibitory role through intramolecular interactions with a proline-rich region N-terminal to the DH 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 2077087849 241 QTLRAlfqYKPQNIDELMINAGDFIYVnpTQQSevSEGWVIGTSHQSGCRGFLPENYTE 299
Cdd:cd11940     3 QCIRS---YKAQENDELTLEKADIIMV--RQQS--SDGWLEGVRLSDGERGWFPQSHVE 54

Src Homology 3 domain of alpha-Pak Interactive eXchange factor; Alpha-PIX, also called Rho guanine nucleotide exchange factor 6 (ARHGEF6) or Cool (Cloned out of Library)-2, activates small GTPases by exchanging bound GDP for free GTP. It acts as a GEF for both Cdc42 and Rac 1, and is localized in dendritic spines where it regulates spine morphogenesis. It controls dendritic length and spine density in the hippocampus. Mutations in the ARHGEF6 gene cause X-linked intellectual disability in humans. PIX proteins contain an N-terminal SH3 domain followed by RhoGEF (also called Dbl-homologous or DH) and Pleckstrin Homology (PH) domains, and a C-terminal leucine-zipper domain for dimerization. The SH3 domain of PIX binds to an atypical PxxxPR motif in p21-activated kinases (PAKs) with high affinity. The binding of PAKs to PIX facilitate the localization of PAKs to focal complexes and also localizes PAKs to PIX targets Cdc43 and Rac, leading to the activation of PAKs. 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 2077087849 243 LRALFQYKPQNIDELMINAGDFIYVNPTQQSevseGWVIGTshQSGCRGFLPENYTE 299
Cdd:cd12060     4 VKARFNFKQTNEDELSVCKGDIIYVTRVEEG----GWWEGT--LNGKTGWFPSNYVR 54