The phosphoinositide binding Phox Homology domain of the p40phox subunit of NADPH oxidase; The PX domain is a phosphoinositide binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. p40phox contains an N-terminal PX domain, a central SH3 domain that binds p47phox, and a C-terminal PB1 domain that interacts with p67phox. It is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p40phox positively regulates NADPH oxidase in both phosphatidylinositol-3-phosphate (PI3P)-dependent and PI3P-independent manner. The PX domain is a phospholipid-binding module involved in the membrane targeting of proteins. The p40phox PX domain binds to PI3P, an abundant lipid in phagosomal membranes, playing an important role in the localization of NADPH oxidase. The PX domain of p40phox is also involved in protein-protein interaction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 254540078  19 DVAVSANIADIEEKRGFTSHFVFVIEVKTKGGSKYLIYRRYRQFYALQSKLEERFGPESKNSPFTCSLPTLPAKVYMGAK 98
Cdd:cd06882    1 DVAVSATIADIEEKRGFTNYYVFVIEVKTKGGSKYLIYRRYRQFFALQSKLEERFGPEAGSSAYDCTLPTLPGKIYVGRK 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|...
gi 254540078  99 QEIAETRIPALNAYMKNLLSLPVCVLMDPDVRIFFYQSAYDAE 141
Cdd:cd06882   81 AEIAERRIPLLNRYMKELLSLPVWVLMDEDVRLFFYQTESDSE 123

Src Homology 3 domain of the p40phox subunit of NADPH oxidase; p40phox, also called Neutrophil cytosol factor 4 (NCF-4), is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p40phox positively regulates NADPH oxidase in both phosphatidylinositol-3-phosphate (PI3P)-dependent and PI3P-independent manner. It contains an N-terminal PX domain, a central SH3 domain, and a C-terminal PB1 domain that interacts with p67phox. The SH3 domain of p40phox binds to canonical polyproline and noncanonical motifs at the C-terminus of p47phox. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKIL 227
Cdd:cd11869    1 RAEALFDFTGNSKLELNFKAGDVIFLLSRVNKDWLEGTVRGATGIFPLSFVKII 54

The phosphoinositide binding Phox Homology domain of the p40phox subunit of NADPH oxidase; The PX domain is a phosphoinositide binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. p40phox contains an N-terminal PX domain, a central SH3 domain that binds p47phox, and a C-terminal PB1 domain that interacts with p67phox. It is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p40phox positively regulates NADPH oxidase in both phosphatidylinositol-3-phosphate (PI3P)-dependent and PI3P-independent manner. The PX domain is a phospholipid-binding module involved in the membrane targeting of proteins. The p40phox PX domain binds to PI3P, an abundant lipid in phagosomal membranes, playing an important role in the localization of NADPH oxidase. The PX domain of p40phox is also involved in protein-protein interaction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 254540078  19 DVAVSANIADIEEKRGFTSHFVFVIEVKTKGGSKYLIYRRYRQFYALQSKLEERFGPESKNSPFTCSLPTLPAKVYMGAK 98
Cdd:cd06882    1 DVAVSATIADIEEKRGFTNYYVFVIEVKTKGGSKYLIYRRYRQFFALQSKLEERFGPEAGSSAYDCTLPTLPGKIYVGRK 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|...
gi 254540078  99 QEIAETRIPALNAYMKNLLSLPVCVLMDPDVRIFFYQSAYDAE 141
Cdd:cd06882   81 AEIAERRIPLLNRYMKELLSLPVWVLMDEDVRLFFYQTESDSE 123

Src Homology 3 domain of the p40phox subunit of NADPH oxidase; p40phox, also called Neutrophil cytosol factor 4 (NCF-4), is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p40phox positively regulates NADPH oxidase in both phosphatidylinositol-3-phosphate (PI3P)-dependent and PI3P-independent manner. It contains an N-terminal PX domain, a central SH3 domain, and a C-terminal PB1 domain that interacts with p67phox. The SH3 domain of p40phox binds to canonical polyproline and noncanonical motifs at the C-terminus of p47phox. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKIL 227
Cdd:cd11869    1 RAEALFDFTGNSKLELNFKAGDVIFLLSRVNKDWLEGTVRGATGIFPLSFVKII 54

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 254540078   171 EAPRAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQ-GATGIFPGSFVK 225
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRLGrGKEGLFPSNYVE 56

PB1 domain; Phox and Bem1p domain, present in many eukaryotic cytoplasmic signalling proteins. The domain adopts a beta-grasp fold, similar to that found in ubiquitin and Ras-binding domains. A motif, variously termed OPR, PC and AID, represents the most conserved region of the majority of PB1 domains, and is necessary for PB1 domain function. This function is the formation of PB1 domain heterodimers, although not all PB1 domain pairs associate.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 254540078   237 TNWLRCYFYEDTgktiKDIAVEEDLSstplFKDLLALMRREFQRE--DIALSYQDAEGDLVRLLSDEDVGLMVKQARGLP 314
Cdd:smart00666   1 TVDVKLRYGGET----RRLSVPRDIS----FEDLRSKVAKRFGLDnqSFTLKYQDEDGDLVSLTSDEDLEEAIEEYDSLG 72

                           90
                   ....*....|..
gi 254540078   315 SQKrlfpWKLHV 326
Cdd:smart00666  73 SKK----LRLHV 80

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 254540078  174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKIL 227
Cdd:pfam07653   1 YGRVIFDYVGTDKNGLTLKKGDVVKVLGKDNDGWWEGETGGRVGLVPSTAVEEI 54

The phosphoinositide binding Phox Homology domain of the p40phox subunit of NADPH oxidase; The PX domain is a phosphoinositide binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. p40phox contains an N-terminal PX domain, a central SH3 domain that binds p47phox, and a C-terminal PB1 domain that interacts with p67phox. It is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p40phox positively regulates NADPH oxidase in both phosphatidylinositol-3-phosphate (PI3P)-dependent and PI3P-independent manner. The PX domain is a phospholipid-binding module involved in the membrane targeting of proteins. The p40phox PX domain binds to PI3P, an abundant lipid in phagosomal membranes, playing an important role in the localization of NADPH oxidase. The PX domain of p40phox is also involved in protein-protein interaction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 254540078  19 DVAVSANIADIEEKRGFTSHFVFVIEVKTKGGSKYLIYRRYRQFYALQSKLEERFGPESKNSPFTCSLPTLPAKVYMGAK 98
Cdd:cd06882    1 DVAVSATIADIEEKRGFTNYYVFVIEVKTKGGSKYLIYRRYRQFFALQSKLEERFGPEAGSSAYDCTLPTLPGKIYVGRK 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|...
gi 254540078  99 QEIAETRIPALNAYMKNLLSLPVCVLMDPDVRIFFYQSAYDAE 141
Cdd:cd06882   81 AEIAERRIPLLNRYMKELLSLPVWVLMDEDVRLFFYQTESDSE 123

Src Homology 3 domain of the p40phox subunit of NADPH oxidase; p40phox, also called Neutrophil cytosol factor 4 (NCF-4), is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p40phox positively regulates NADPH oxidase in both phosphatidylinositol-3-phosphate (PI3P)-dependent and PI3P-independent manner. It contains an N-terminal PX domain, a central SH3 domain, and a C-terminal PB1 domain that interacts with p67phox. The SH3 domain of p40phox binds to canonical polyproline and noncanonical motifs at the C-terminus of p47phox. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKIL 227
Cdd:cd11869    1 RAEALFDFTGNSKLELNFKAGDVIFLLSRVNKDWLEGTVRGATGIFPLSFVKII 54

The Phox Homology domain, a phosphoinositide binding module; The PX domain is a phosphoinositide (PI) binding module involved in targeting proteins to membranes. Proteins containing PX domains interact with PIs and have been implicated in highly diverse functions such as cell signaling, vesicular trafficking, protein sorting, lipid modification, cell polarity and division, activation of T and B cells, and cell survival. Many members of this superfamily bind phosphatidylinositol-3-phosphate (PI3P) but in some cases, other PIs such as PI4P or PI(3,4)P2, among others, are the preferred substrates. In addition to protein-lipid interaction, the PX domain may also be involved in protein-protein interaction, as in the cases of p40phox, p47phox, and some sorting nexins (SNXs). The PX domain is conserved from yeast to humans and is found in more than 100 proteins. The majority of PX domain-containing proteins are SNXs, which play important roles in endosomal sorting.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 254540078  23 SANIADIEEKRGFT-SHFVFVIEVKTKGGSKYLIYRRYRQFYALQSKLEERFGPesknspftCSLPTLPAKVYMGAK-QE 100
Cdd:cd06093    1 SVSIPDYEKVKDGGkKYVVYIIEVTTQGGEEWTVYRRYSDFEELHEKLKKKFPG--------VILPPLPPKKLFGNLdPE 72

                         90       100       110
                 ....*....|....*....|....*....|...
gi 254540078 101 IAETRIPALNAYMKNLLSLPVCVLmDPDVRIFF 133
Cdd:cd06093   73 FIEERRKQLEQYLQSLLNHPELRN-SEELKEFL 104

The phosphoinositide binding Phox Homology domain of Five SH protein; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. Five SH (FISH), also called Tks5, is a scaffolding protein and Src substrate that is localized in podosomes, which are electron-dense structures found in Src-transformed fibroblasts, osteoclasts, macrophages, and some invasive cancer cells. FISH contains an N-terminal PX domain and five Src homology 3 (SH3) domains. FISH binds and regulates some members of the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. It is required for podosome formation, degradation of the extracellular matrix, and cancer cell invasion. This subfamily also includes proteins with a different number of SH3 domains than FISH, such as Tks4, which contains four SH3 domains instead of five. The Tks4 adaptor protein is required for the formation of functional podosomes. It has overlapping, but not identical, functions as FISH. The PX domain is involved in targeting of proteins to PI-enriched membranes, and may also be involved in protein-protein interaction.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 254540078  22 VSANIADIEEKRGFTSHFVFVIEVKTKGGSKYLIYRRYRQFYALQSKLEERFGPES-KNSPFTCSLPTLPAKVYMGAK-- 98
Cdd:cd06888    2 KDVKVIDVEKRRAPSKHYVYIINVTWSDGSSNVIYRRYSKFFDLQMQLLDKFPIEGgQKDPSQRIIPFLPGKILFRRShi 81

                         90       100
                 ....*....|....*....|..
gi 254540078  99 QEIAETRIPALNAYMKNLLSLP 120
Cdd:cd06888   82 RDVAVKRLKPIDEYCKALVRLP 103

First 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 first 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 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11781    2 ARALYPFKAQSAKELSLKKGDIIYIRRQIDKNWYEGEHNGRVGIFPASYVEI 53

C-terminal (or second) Src Homology 3 domain of the p67phox subunit of NADPH oxidase; p67phox, also called Neutrophil cytosol factor 2 (NCF-2), is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p67phox plays a regulatory role and contains N-terminal TPR, first SH3 (or N-terminal or central SH3), PB1, and C-terminal SH3 domains. It binds, via its C-terminal SH3 domain, to a proline-rich region of p47phox and upon activation, this complex assembles with flavocytochrome b558, the Nox2-p22phox heterodimer. Concurrently, RacGTP translocates to the membrane and interacts with the TPR domain of p67phox, which leads to the activation of NADPH oxidase. The PB1 domain of p67phox binds to its partner PB1 domain in p40phox, and this facilitates the assembly of p47phox-p67phox at the membrane. 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 254540078 176 EALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVK 225
Cdd:cd12046    3 VALFSYEASQPEDLEFQKGDVILVLSKVNEDWLEGQCKGKIGIFPSAFVE 52

Second Src Homology 3 domain of Sorbin and SH3 domain containing (Sorbs) proteins and similar domains; This family, also called the vinexin family, is composed predominantly of adaptor proteins containing one sorbin homology (SoHo) and three SH3 domains. Members include the second SH3 domains of Sorbs1 (or ponsin), Sorbs2 (or ArgBP2), Vinexin (or Sorbs3), and similar domains. They are involved in the regulation of cytoskeletal organization, cell adhesion, and growth factor signaling. Members of this family bind multiple partners including signaling molecules like c-Abl, c-Arg, Sos, and c-Cbl, as well as cytoskeletal molecules such as vinculin and afadin. They may have overlapping functions. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11782    1 EARAKYNFNADTGVELSFRKGDVITLTRRVDENWYEGRIGGRQGIFPVSYVQV 53

Src homology 3 domain of SH3 domain containing Ysc84-like 1 (SH3YL1) protein; SH3YL1 localizes to the plasma membrane and is required for dorsal ruffle formation. It binds phosphoinositides (PIs) with high affinity through its N-terminal SYLF domain (also called DUF500). In addition, SH3YL1 contains a C-terminal SH3 domain which has been reported to bind to N-WASP, dynamin 2, and SHIP2 (a PI 5-phosphatase). 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 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINK--DWLEGTSQGATGIFPGSFVK 225
Cdd:cd11841    2 VTALYSFEGQQPCDLSFQAGDRITVLTRTDSqfDWWEGRLRGRVGIFPANYVS 54

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVK 225
Cdd:cd11805    1 RVQALYDFNPQEPGELEFRRGDIITVLDSSDPDWWKGELRGRVGIFPANYVQ 52

First 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
                 ....*....|....*....|....*....|....*....|....*....|.
gi 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVK 225
Cdd:cd11920    3 ARAVYDFKAQTSKELSFKKGDTVYILRKIDQNWYEGEHHGRVGIFPISYVE 53

C-terminal Src Homology 3 domain of the p67phox subunit of NADPH oxidase and similar proteins; This subfamily is composed of p67phox, NADPH oxidase activator 1 (Noxa1), and similar proteins. p67phox, also called Neutrophil cytosol factor 2 (NCF-2), and Noxa1 are homologs and are the cytosolic subunits of the phagocytic (Nox2) and nonphagocytic (Nox1) NADPH oxidase complexes, respectively. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p67phox and Noxa1 play regulatory roles. p67phox contains N-terminal TPR, first SH3 (or N-terminal or central SH3), PB1, and C-terminal SH3 domains. Noxa1 has a similar domain architecture except it is lacking the N-terminal SH3 domain. The TPR domain of both binds activated GTP-bound Rac, while the C-terminal SH3 domain of p67phox and Noxa1 binds the polyproline motif found at the C-terminus of p47phox and Noxo1, respectively. 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 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVK 225
Cdd:cd11870    1 QVVALHRYEAQGPEDLGFREGDTIDVLSEVNEAWLEGHSDGRVGIFPKCFVV 52

Src homology 3 domain of Ysc84p and similar fungal proteins; This family is composed of the Saccharomyces cerevisiae proteins, Ysc84p (also called LAS17-binding protein 4, Lsb4p) and Lsb3p, and similar fungal proteins. They contain an N-terminal SYLF domain (also called DUF500) and a C-terminal SH3 domain. Ysc84p localizes to actin patches and plays an important in actin polymerization during endocytosis. The N-terminal domain of both Ysc84p and Lsb3p can bind and bundle actin filaments. A study of the yeast SH3 domain interactome predicts that the SH3 domains of Lsb3p and Lsb4p may function as molecular hubs for the assembly of endocytic complexes. 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 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINK--DWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11842    1 KAVALYDFAGEQPGDLAFQKGDIITILKKSDSqnDWWTGRIGGREGIFPANYVEL 55

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 254540078  174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKIL 227
Cdd:pfam07653   1 YGRVIFDYVGTDKNGLTLKKGDVVKVLGKDNDGWWEGETGGRVGLVPSTAVEEI 54

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 254540078  177 ALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQ-GATGIFP 220
Cdd:pfam00018   2 ALYDYTAQEPDELSFKKGDIIIVLEKSEDGWWKGRNKgGKEGLIP 46

First Src Homology 3 domain of SH3 domain containing ring finger proteins; This model represents the first SH3 domain of SH3RF1 (or POSH), SH3RF2 (or POSHER), SH3RF3 (POSH2), and similar domains. Members of this family are scaffold proteins that function as E3 ubiquitin-protein ligases. They all contain an N-terminal RING finger domain and multiple SH3 domains; SH3RF1 and SH3RF3 have four SH3 domains while SH3RF2 has three. SH3RF1 plays a role in calcium homeostasis through the control of the ubiquitin domain protein Herp. It may also have a role in regulating death receptor mediated and JNK mediated apoptosis. SH3RF3 interacts with p21-activated kinase 2 (PAK2) and GTP-loaded Rac1. It may play a role in regulating JNK mediated apoptosis in certain conditions. SH3RF2 acts as an anti-apoptotic regulator of the JNK pathway by binding to and promoting the degradation of SH3RF1. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11786    1 CAKALYNYEGKEPGDLSFKKGDIILLRKRIDENWYHGECNGKQGFFPASYVQV 53

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 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11877    2 VRAKFNFEGTNEDELSFDKGDIITVTQVVEGGWWEGTLNGKTGWFPSNYVKE 53

Src homology 3 domain of Abl Interactor proteins; Abl interactor (Abi) proteins are adaptor proteins serving as binding partners and substrates of Abl tyrosine kinases. They are involved in regulating actin cytoskeletal reorganization and play important roles in membrane-ruffling, endocytosis, cell motility, and cell migration. They localize to sites of actin polymerization in epithelial adherens junction and immune synapses, as well as to the leading edge of lamellipodia. Vertebrates contain two Abi proteins, Abi1 and Abi2. Abi1 displays a wide expression pattern while Abi2 is highly expressed in the eye and brain. Abi proteins contain a homeobox homology domain, a proline-rich region, and a SH3 domain. The SH3 domain of Abi binds to a PxxP motif in Abl. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 254540078 177 ALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFV 224
Cdd:cd11826    4 ALYDYTADKDDELSFQEGDIIYVTKKNDDGWYEGVLNGVTGLFPGNYV 51

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 254540078 177 ALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11996    5 AMYDYTANNEDELSFSKGQLINVLNKDDPDWWQGEINGVTGLFPSNYVKM 54

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11956    4 AVACFDYTGRTAQELSFKRGDVLLLHSKASSDWWRGEHNGMRGLIPHKYISV 55

Src Homology 3 domain of GTPase Regulator Associated with Focal adhesion kinase and similar proteins; This subfamily is composed of Rho GTPase activating proteins (GAPs) with similarity to GRAF. Members contain an N-terminal BAR domain, followed by a Pleckstrin homology (PH) domain, a Rho GAP domain, and a C-terminal SH3 domain. Although vertebrates harbor four Rho GAPs in the GRAF subfamily including GRAF, GRAF2, GRAF3, and Oligophrenin-1 (OPHN1), only three are included in this model. OPHN1 contains the BAR, PH and GAP domains, but not the C-terminal SH3 domain. GRAF and GRAF2 show GAP activity towards RhoA and Cdc42. GRAF influences Rho-mediated cytoskeletal rearrangements and binds focal adhesion kinase. GRAF2 regulates caspase-activated p21-activated protein kinase-2. The SH3 domain of GRAF and GRAF2 binds PKNbeta, a target of the small GTPase Rho. SH3 domains bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs; they play a role in the regulation of enzymes by intramolecular interactions, changing the subcellular localization of signal pathway components and mediate multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKD-WLEGTSQGATGIFPGSFVKI 226
Cdd:cd11882    1 RARALYACKAEDESELSFEPGQIITNVQPSDEPgWLEGTLNGRTGLIPENYVEF 54

Second Src homology 3 domain of ADAM-binding protein Eve-1; Eve-1, also called SH3 domain-containing protein 19 (SH3D19) or EEN-binding protein (EBP), exists in multiple alternatively spliced isoforms. The longest isoform contains five SH3 domain in the C-terminal region and seven proline-rich motifs in the N-terminal region. It is abundantly expressed in skeletal muscle and heart, and may be involved in regulating the activity of ADAMs (A disintegrin and metalloproteases). Eve-1 interacts with EEN, an endophilin involved in endocytosis and may be the target of the MLL-EEN fusion protein that is implicated in leukemogenesis. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVK 225
Cdd:cd11815    2 AVVLHDFPAEHSDDLSLNSGEIVYLLEKIDTEWYRGKCKNTTGIFPANHVK 52

Src homology 3 domain of APC-Stimulated guanine nucleotide Exchange Factor 2; ASEF2, also called Spermatogenesis-associated protein 13 (SPATA13), is a GEF that localizes with actin at the leading edge of cells and is important in cell migration and adhesion dynamics. GEFs activate small GTPases by exchanging bound GDP for free GTP. ASEF2 can activate both Rac 1 and Cdc42, but only Rac1 activation is necessary for increased cell migration and adhesion turnover. Together with APC (adenomatous polyposis coli) and Neurabin2, a scaffold protein that binds F-actin, it is involved in regulating HGF-induced cell migration. ASEF2 contains a SH3 domain followed by RhoGEF (also called Dbl-homologous or DH) and Pleckstrin Homology (PH) domains. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11974    3 AEALWDHVTMDDQELAFKAGDVIRVLEASNKDWWWGRNEDREAWFPASFVRL 54

The phosphoinositide binding Phox Homology Domain of Class II Phosphoinositide 3-Kinases; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. The Phosphoinositide 3-Kinase (PI3K) family of enzymes catalyzes the phosphorylation of the 3-hydroxyl group of the inositol ring of phosphatidylinositol. PI3Ks play an important role in a variety of fundamental cellular processes, including cell motility, the Ras pathway, vesicle trafficking and secretion, immune cell activation and apoptosis. They are also involved in the regulation of clathrin-mediated membrane trafficking as well as ATP-dependent priming of neurosecretory granule exocytosis. PI3Ks are divided into three main classes (I, II, and III) based on their substrate specificity, regulation, and domain structure. Class II PI3Ks preferentially use PI as a substrate to produce PI3P, but can also phosphorylate PI4P to produce PI(3,4)P2. They function as monomers and do not associate with any regulatory subunits. Class II enzymes contain an N-terminal Ras binding domain, a lipid binding C2 domain, a PI3K homology domain of unknown function, an ATP-binding cataytic domain, a PX domain, and a second C2 domain at the C-terminus. Class II PI3Ks include three vertebrate isoforms (alpha, beta, and gamma), the Drosophila PI3K_68D, and similar proteins.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 254540078  23 SANIADIEEKRGFTSHFVFVIEVKTKGGSK-YLIYRRYRQFYALQSKLEERFgPESKnspftcsLPTLPAKVYMGAKQ-- 99
Cdd:cd06883    1 EVSVFGFQKRYSPEKYYIYVVKVTRENQTEpSFVFRTFEEFQELHNKLSLLF-PSLK-------LPSFPARVVLGRSHik 72

                         90       100       110
                 ....*....|....*....|....*....|....*
gi 254540078 100 EIAETRIPALNAYMKNLLSLPVCVLMDPDVRIFFY 134
Cdd:cd06883   73 QVAERRKIELNSYLKSLFNASPEVAESDLVYTFFH 107

Second 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 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGAT--GIFPGSFVKILK 228
Cdd:cd11922    3 AIAKFNFNGDTQVEMSFRKGERITLLRQVDENWYEGRIPGTSrqGIFPITYVDVIK 58

Src homology 3 domain of Abl Interactor 1; Abi1, also called e3B1, is a central regulator of actin cytoskeletal reorganization through interactions with many protein complexes. It is part of WAVE, a nucleation-promoting factor complex, that links Rac 1 activation to actin polymerization causing lamellipodia protrusion at the plasma membrane. Abi1 interact with formins to promote protrusions at the leading edge of motile cells. It also is a target of alpha4 integrin, regulating membrane protrusions at sites of integrin engagement. Abi proteins are adaptor proteins serving as binding partners and substrates of Abl tyrosine kinases. They are involved in regulating actin cytoskeletal reorganization and play important roles in membrane-ruffling, endocytosis, cell motility, and cell migration. Abi proteins contain a homeobox homology domain, a proline-rich region, and a SH3 domain. The SH3 domain of Abi binds to a PxxP motif in Abl. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 254540078 177 ALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVK 225
Cdd:cd11971    4 AIYDYSKDKDDELSFMEGAIIYVIKKNDDGWYEGVCNGVTGLFPGNYVE 52

Src homology 3 domain of Abl Interactor 2; Abi2 is highly expressed in the brain and eye. It regulates actin cytoskeletal reorganization at adherens junctions and dendritic spines, which is important in cell morphogenesis, migration, and cognitive function. Mice deficient with Abi2 show defects in orientation and migration of lens fibers, neuronal migration, dendritic spine morphology, as well as deficits in learning and memory. Abi proteins are adaptor proteins serving as binding partners and substrates of Abl tyrosine kinases. They are involved in regulating actin cytoskeletal reorganization and play important roles in membrane-ruffling, endocytosis, cell motility, and cell migration. Abi proteins contain a homeobox homology domain, a proline-rich region, and a SH3 domain. The SH3 domain of Abi binds to a PxxP motif in Abl. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 254540078 177 ALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVK 225
Cdd:cd11972    7 AIYDYTKDKEDELSFQEGAIIYVIKKNDDGWYEGVMNGVTGLFPGNYVE 55

Second 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
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGAT--GIFPGSFVKIL 227
Cdd:cd11923    3 AVAKYNFNADTNVELSLRKGDRVVLLKQVDQNWYEGKIPGTNrqGIFPVSYVEVI 57

Second 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 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEG--TSQGATGIFPGSFVKI 226
Cdd:cd11924    3 AVAQYTFKGDLEVELSFRKGEHICLIRKVNENWYEGriTGTGRQGIFPASYVQV 56

Src Homology 3 domain of Sorting nexin 18; SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1. It binds FIP5 and is required for apical lumen formation. It may also play a role in axonal elongation. SNXs are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNX18 also contains BAR and SH3 domains. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKD-WLEGT-SQGATGIFPGSFVKI 226
Cdd:cd11897    1 RARALYDFRSENPGEISLREHEVLSLCSEQDIEgWLEGVnSRGDRGLFPASYVEV 55

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 254540078 177 ALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11873    4 VEFDYDAEEPDELTLKVGDIITNVKKMEEGWWEGTLNGKRGMFPDNFVKV 53

Src homology 3 domain of Slit-Robo GTPase Activating Proteins 1, 2, and 3; srGAP1, also called Rho GTPase-Activating Protein 13 (ARHGAP13), is a Cdc42- and RhoA-specific GAP and is expressed later in the development of central nervous system tissues. srGAP2 is expressed in zones of neuronal differentiation. It plays a role in the regeneration of neurons and axons. srGAP3, also called MEGAP (MEntal disorder associated GTPase-Activating Protein), is a Rho GAP with activity towards Rac1 and Cdc42. It impacts cell migration by regulating actin and microtubule cytoskeletal dynamics. The association between srGAP3 haploinsufficiency and mental retardation is under debate. srGAPs are Rho GAPs that interact with Robo1, the transmembrane receptor of Slit proteins. Slit proteins are secreted proteins that control axon guidance and the migration of neurons and leukocytes. srGAPs contain an N-terminal F-BAR domain, a Rho GAP domain, and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11955    2 AIAKFDYVGRSARELSFKKGASLLLYHRASDDWWEGRHNGIDGLVPHQYIVV 53

First Src Homology 3 domain of SH3 domain containing ring finger protein 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 first SH3 domain, located at the N-terminal half, of SH3RF1. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 254540078 173 PRAEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11927    1 PCAKALYNYEGKEPGDLKFSKGDIIILRRQVDENWYHGEVNGIHGFFPTNFVQI 54

Src Homology 3 domain of Sorting Nexin 33; SNX33 interacts with Wiskott-Aldrich syndrome protein (WASP) and plays a role in the maintenance of cell shape and cell cycle progression. It modulates the shedding and endocytosis of cellular prion protein (PrP(c)) and amyloid precursor protein (APP). SNXs are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNX33 also contains BAR and SH3 domains. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 254540078 174 RAEALFDFTGNSKLELSFKAGDVIFLLSKINKD-WLEGT-SQGATGIFPGSFVKI 226
Cdd:cd11896    1 KARALYSFQSENKEEINIQENEELVIFSENSLDgWLQGQnSRGETGLFPASYVEI 55

Src homology 3 domain of Hematopoietic lineage cell-specific protein 1; HS1, also called HCLS1 (hematopoietic cell-specific Lyn substrate 1), is a cortactin homolog expressed specifically in hematopoietic cells. It is an actin regulatory protein that binds the Arp2/3 complex and stabilizes branched actin filaments. It is required for cell spreading and signaling in lymphocytes. It regulates cytoskeletal remodeling that controls lymphocyte trafficking, and it also affects tissue invasion and infiltration of leukemic B cells. Like cortactin, HS1 contains an N-terminal acidic domain, several copies of a repeat domain found in cortactin and HS1, a proline-rich region, and a C-terminal SH3 domain. The N-terminal region binds the Arp2/3 complex and F-actin, while the C-terminal region acts as an adaptor or scaffold that can connect varied 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 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKIL 227
Cdd:cd12073    3 AVALYDYQGEGDDEISFDPQETITDIEMVDEGWWKGTCHGHRGLFPANYVELL 55

Src homology 3 domain of APC-Stimulated guanine nucleotide Exchange Factor; ASEF, also called ARHGEF4, exists in an autoinhibited form and is activated upon binding of the tumor suppressor APC (adenomatous polyposis coli). GEFs activate small GTPases by exchanging bound GDP for free GTP. ASEF can activate Rac1 or Cdc42. Truncated ASEF, which is found in colorectal cancers, is constitutively active and has been shown to promote angiogenesis and cancer cell migration. ASEF contains a SH3 domain followed by RhoGEF (also called Dbl-homologous or DH) and Pleckstrin Homology (PH) domains. In its autoinhibited form, the SH3 domain of ASEF forms an extensive interface with the DH and PH domains, blocking the Rac 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 254540078 175 AEALFDFTGNSKLELSFKAGDVIFLLSKINKDWLEGTSQGATGIFPGSFVKI 226
Cdd:cd11973   20 AEALWDHVTMDDQELGFKAGDVIEVMDATNKEWWWGRVLDSEGWFPASFVRL 71