C2 domain; The C2 domain was first identified in PKC. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 422 VRNDIYITLLQGDFDKYNKTTQRNVEVIMCVCAEDGKTLPNAICVGAGDKPMNEYRSVVYYQVKQPRWMETVKVAVPIED 501
Cdd:cd08694    1 VRNDLYLTLVQGDFDKGSKTSDKNVEVTVSVCNEDGKIIPGVISLGAGEEPIDEYKSVIYYQVDKPKWFETFKVAIPIED 80

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 502 MQRIHLRFMFRHRSSLESKDKGEKNFAMSYVKLMKEDGTTLHDGFHDLVVLKGDSKK-MEDASAYLTLPSYRHHVENKGa 580
Cdd:cd08694   81 FKSSHLRFTFKHRSSNEAKDKSEKPFALSFVKLMQENGTTLTDGEHDLIVYKVDAKKkLEDAKAYLSLPSTRAELEARK- 159

                        170       180       190
                 ....*....|....*....|....*....|....*..
gi 767938119 581 TLSRSSSSVGGLSVSSRDVFSISTLVCSTKLTQNVGL 617
Cdd:cd08694  160 SSPSGSASNLGLSLSSKDSFQISTLVCSTKLTQNVDL 196

C2 domains found in Dedicator Of CytoKinesis (Dock) class A proteins; Dock-A is one of 4 classes of Dock family proteins. The members here include: Dock180/Dock1, Dock2, and Dock5. Most of these members have been shown to be GEFs specific for Rac. Dock5 has not been well characterized to date, but most likely also is a GEF specific for Rac. In addition to the C2 domain (AKA Dock homology region (DHR)-1, CED-5, Dock180, MBC-zizimin homology (CZH) 1) and the DHR-2 (AKA CZH2, or Docker), which all Dock180-related proteins have, Dock-A members contain a proline-rich region and a SH3 domain upstream of the C2 domain. DHR-2 has the catalytic activity for Rac and/or Cdc42, but is structurally unrelated to the DH domain. The C2/DHR-1 domains of Dock180 and Dock4 have been shown to bind phosphatidylinositol-3, 4, 5-triphosphate (PtdIns(3,4,5)P3). The C2 domain was first identified in PKC. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 422 VRNDIYITLLQGDFDKYNKTTQRNVEVIMCVCAEDGKTLPNAICVGAGDKPMNEYRSVVYYQVKQPRWMETVKVAVPIED 501
Cdd:cd08694    1 VRNDLYLTLVQGDFDKGSKTSDKNVEVTVSVCNEDGKIIPGVISLGAGEEPIDEYKSVIYYQVDKPKWFETFKVAIPIED 80

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 502 MQRIHLRFMFRHRSSLESKDKGEKNFAMSYVKLMKEDGTTLHDGFHDLVVLKGDSKK-MEDASAYLTLPSYRHHVENKGa 580
Cdd:cd08694   81 FKSSHLRFTFKHRSSNEAKDKSEKPFALSFVKLMQENGTTLTDGEHDLIVYKVDAKKkLEDAKAYLSLPSTRAELEARK- 159

                        170       180       190
                 ....*....|....*....|....*....|....*..
gi 767938119 581 TLSRSSSSVGGLSVSSRDVFSISTLVCSTKLTQNVGL 617
Cdd:cd08694  160 SSPSGSASNLGLSLSSKDSFQISTLVCSTKLTQNVDL 196

Src Homology 3 domain of Class A Dedicator of Cytokinesis protein 2; Dock2 is a hematopoietic cell-specific, class A DOCK and is an atypical guanine nucleotide exchange factor (GEF) that lacks the conventional Dbl homology (DH) domain. It plays an important role in lymphocyte migration and activation, T-cell differentiation, neutrophil chemotaxis, and type I interferon induction. All DOCKs contain two homology domains: the DHR-1 (Dock homology region-1), also called CZH1 (CED-5, Dock180, and MBC-zizimin homology 1), and DHR-2 (also called CZH2 or Docker). The DHR-1 domain binds phosphatidylinositol-3,4,5-triphosphate while DHR-2 contains the catalytic activity for Rac and/or Cdc42. Class A DOCKs also contain an SH3 domain at the N-terminal region and a PxxP motif at the C-terminus; they are specific GEFs for Rac. The SH3 domain of Dock2 binds to DHR-2 in an autoinhibitory manner; binding of the scaffold protein Elmo to the SH3 domain of Dock2 exposes the DHR-2 domain and promotes GEF activity. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 767938119  12 HGVAIYNFQGSGAPQLSLQIGDVVRIQETCGDWYRGYLIKHKMLQGIFPKSFIHIK 67
Cdd:cd12050    1 YGVAIYNFKGSGVPQLSLQIGDVVHIQETCEDWYKGYLVRHKDLQGIFPKSFIHIK 56

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 767938119   12 HGVAIYNFQGSGAPQLSLQIGDVVRIQET-CGDWYRGYLIKHKmlqGIFPKSFI 64
Cdd:pfam07653   1 YGRVIFDYVGTDKNGLTLKKGDVVKVLGKdNDGWWEGETGGRV---GLVPSTAV 51

C2 domains found in Dedicator Of CytoKinesis (Dock) class A proteins; Dock-A is one of 4 classes of Dock family proteins. The members here include: Dock180/Dock1, Dock2, and Dock5. Most of these members have been shown to be GEFs specific for Rac. Dock5 has not been well characterized to date, but most likely also is a GEF specific for Rac. In addition to the C2 domain (AKA Dock homology region (DHR)-1, CED-5, Dock180, MBC-zizimin homology (CZH) 1) and the DHR-2 (AKA CZH2, or Docker), which all Dock180-related proteins have, Dock-A members contain a proline-rich region and a SH3 domain upstream of the C2 domain. DHR-2 has the catalytic activity for Rac and/or Cdc42, but is structurally unrelated to the DH domain. The C2/DHR-1 domains of Dock180 and Dock4 have been shown to bind phosphatidylinositol-3, 4, 5-triphosphate (PtdIns(3,4,5)P3). The C2 domain was first identified in PKC. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 422 VRNDIYITLLQGDFDKYNKTTQRNVEVIMCVCAEDGKTLPNAICVGAGDKPMNEYRSVVYYQVKQPRWMETVKVAVPIED 501
Cdd:cd08694    1 VRNDLYLTLVQGDFDKGSKTSDKNVEVTVSVCNEDGKIIPGVISLGAGEEPIDEYKSVIYYQVDKPKWFETFKVAIPIED 80

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 502 MQRIHLRFMFRHRSSLESKDKGEKNFAMSYVKLMKEDGTTLHDGFHDLVVLKGDSKK-MEDASAYLTLPSYRHHVENKGa 580
Cdd:cd08694   81 FKSSHLRFTFKHRSSNEAKDKSEKPFALSFVKLMQENGTTLTDGEHDLIVYKVDAKKkLEDAKAYLSLPSTRAELEARK- 159

                        170       180       190
                 ....*....|....*....|....*....|....*..
gi 767938119 581 TLSRSSSSVGGLSVSSRDVFSISTLVCSTKLTQNVGL 617
Cdd:cd08694  160 SSPSGSASNLGLSLSSKDSFQISTLVCSTKLTQNVDL 196

C2 domains found in Dedicator Of CytoKinesis (Dock) class B proteins; Dock-B is one of 4 classes of Dock family proteins. The members here include: Dock3/MOCA (modifier of cell adhesion) and Dock4. Most of these members have been shown to be GEFs specific for Rac, although Dock4 has also been shown to interact indirectly with the Ras family GTPase Rap1, probably through Rap regulatory proteins. In addition to the C2 domain (AKA Dock homology region (DHR)-1, CED-5, Dock180, MBC-zizimin homology (CZH) 1) and the DHR-2 (AKA CZH2, or Docker), which all Dock180-related proteins have, Dock-B members contain a SH3 domain upstream of the C2 domain and a proline-rich region downstream. DHR-2 has the catalytic activity for Rac and/or Cdc42, but is structurally unrelated to the DH domain. The C2/DHR-1 domains of Dock180 and Dock4 have been shown to bind phosphatidylinositol-3, 4, 5-triphosphate (PtdIns(3,4,5)P3). The C2 domain was first identified in PKC. C2 domains fold into an 8-standed beta-sandwich that can adopt 2 structural arrangements: Type I and Type II, distinguished by a circular permutation involving their N- and C-terminal beta strands. Many C2 domains are Ca2+-dependent membrane-targeting modules that bind a wide variety of substances including bind phospholipids, inositol polyphosphates, and intracellular proteins. Most C2 domain proteins are either signal transduction enzymes that contain a single C2 domain, such as protein kinase C, or membrane trafficking proteins which contain at least two C2 domains, such as synaptotagmin 1. However, there are a few exceptions to this including RIM isoforms and some splice variants of piccolo/aczonin and intersectin which only have a single C2 domain. C2 domains with a calcium binding region have negatively charged residues, primarily aspartates, that serve as ligands for calcium ions.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 422 VRNDIYITLLQGDFDKYNKTTQRNVEVIMCVCAEDGKTLPNAICVGAGDKPMNEYRSVVYYQVKQPRWMETVKVAVPIED 501
Cdd:cd08695    1 VRNDLYLTLERGEFEKGGKSTAKNIEVTMVVLDADGQVLKDCISLGSGEPPCSEYRSFVLYHNNSPRWNETIKLPIPIDK 80

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767938119 502 MQRIHLRFMFRHRSsleSKDKGEKN-FAMSYVKLMKEDGTTLHDGFHDLVVLKGDSK-KMEDASAYLTLPSYRHHVENKG 579
Cdd:cd08695   81 FRGSHLRFEFRHCS---TKDKGEKKlFGFSFVPLMREDGTTLPDGSHELYVYKCDENaTFLDPALYLGLPCSKEDFQGCP 157

                        170       180       190
                 ....*....|....*....|....*....|....*...
gi 767938119 580 ATlsrsssSVGGLSVSSRDVFSISTLVCSTKLTQNVGL 617
Cdd:cd08695  158 NS------PSPLFSRSSKESFWIRTLLCSTKLTQNVDL 189

Src Homology 3 domain of Class A Dedicator of Cytokinesis protein 2; Dock2 is a hematopoietic cell-specific, class A DOCK and is an atypical guanine nucleotide exchange factor (GEF) that lacks the conventional Dbl homology (DH) domain. It plays an important role in lymphocyte migration and activation, T-cell differentiation, neutrophil chemotaxis, and type I interferon induction. All DOCKs contain two homology domains: the DHR-1 (Dock homology region-1), also called CZH1 (CED-5, Dock180, and MBC-zizimin homology 1), and DHR-2 (also called CZH2 or Docker). The DHR-1 domain binds phosphatidylinositol-3,4,5-triphosphate while DHR-2 contains the catalytic activity for Rac and/or Cdc42. Class A DOCKs also contain an SH3 domain at the N-terminal region and a PxxP motif at the C-terminus; they are specific GEFs for Rac. The SH3 domain of Dock2 binds to DHR-2 in an autoinhibitory manner; binding of the scaffold protein Elmo to the SH3 domain of Dock2 exposes the DHR-2 domain and promotes GEF activity. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 767938119  12 HGVAIYNFQGSGAPQLSLQIGDVVRIQETCGDWYRGYLIKHKMLQGIFPKSFIHIK 67
Cdd:cd12050    1 YGVAIYNFKGSGVPQLSLQIGDVVHIQETCEDWYKGYLVRHKDLQGIFPKSFIHIK 56

Src Homology 3 domain of Class A Dedicator of Cytokinesis proteins 1 and 5; Dock1, also called Dock180, and Dock5 are class A DOCKs and are atypical guanine nucleotide exchange factors (GEFs) that lack the conventional Dbl homology (DH) domain. Dock1 interacts with the scaffold protein Elmo and the resulting complex functions upstream of Rac in many biological events including phagocytosis of apoptotic cells, cell migration and invasion. Dock5 functions upstream of Rac1 to regulate osteoclast function. All DOCKs contain two homology domains: the DHR-1 (Dock homology region-1), also called CZH1 (CED-5, Dock180, and MBC-zizimin homology 1), and DHR-2 (also called CZH2 or Docker). The DHR-1 domain binds phosphatidylinositol-3,4,5-triphosphate while DHR-2 contains the catalytic activity for Rac and/or Cdc42. Class A DOCKs also contain an SH3 domain at the N-terminal region and a PxxP motif at the C-terminus; they are specific GEFs for Rac. The SH3 domain of Dock1 binds to DHR-2 in an autoinhibitory manner; binding of Elmo to the SH3 domain of Dock1 exposes the DHR-2 domain and promotes GEF activity. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 767938119  12 HGVAIYNFQGSGAPQLSLQIGDVVRIQETCGDWYRGYLIKHKMLQGIFPKSFIHIK 67
Cdd:cd12051    1 YGVAIYNYDARGPDELSLQIGDTVHILETYEGWYRGYTLRKKSKKGIFPASYIHLK 56

Src Homology 3 domain of Class B Dedicator of Cytokinesis 3; Dock3, also called modifier of cell adhesion (MOCA), and presenilin binding protein (PBP), is a class B DOCK and is an atypical guanine nucleotide exchange factor (GEF) that lacks the conventional Dbl homology (DH) domain. It regulates N-cadherin dependent cell-cell adhesion, cell polarity, and neuronal morphology. It promotes axonal growth by stimulating actin polymerization and microtubule assembly. All DOCKs contain two homology domains: the DHR-1 (Dock homology region-1), also called CZH1 (CED-5, Dock180, and MBC-zizimin homology 1), and DHR-2 (also called CZH2 or Docker). The DHR-1 domain binds phosphatidylinositol-3,4,5-triphosphate while DHR-2 contains the catalytic activity for Rac and/or Cdc42. Class B DOCKs also contain an SH3 domain at the N-terminal region and a PxxP motif at the C-terminus; Dock3 is a specific GEFs for Rac. The SH3 domain of Dock3 binds to DHR-2 in an autoinhibitory manner; binding of the scaffold protein Elmo to the SH3 domain of Dock3 exposes the DHR-2 domain and promotes GEF activity. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 767938119  12 HGVAIYNFQGSGAPQLSLQIGDVVRIQETCGDWYRGYLIKHKMLQGIFPKSFIHIK 67
Cdd:cd12048    1 YGVVICSFRGSVPQGLVLELGETVQILEKCEGWYRGVSIKKPNVKGIFPANYIHLK 56

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 767938119  14 VAIYNFQGSGAPQLSLQIGDVVRIQETC-GDWYRGYLIKHKmlQGIFPKSF 63
Cdd:cd00174    3 RALYDYEAQDDDELSFKKGDIITVLEKDdDGWWEGELNGGR--EGLFPANY 51

Second Src homology 3 domain (or SH3B) of Intersectin; Intersectins (ITSNs) are adaptor proteins that function in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. They are essential for initiating clathrin-coated pit formation. They bind to many proteins through their multidomain structure and facilitate the assembly of multimeric complexes. Vertebrates contain two ITSN proteins, ITSN1 and ITSN2, which exist in alternatively spliced short and long isoforms. The short isoforms contain two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoforms, in addition, contain RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. ITSN1 and ITSN2 are both widely expressed, with variations depending on tissue type and stage of development. The second SH3 domain (or SH3B) of ITSN1 has been shown to bind WNK and CdGAP. 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 767938119  14 VAIYNFQGSGAPQLSLQIGDVVRIQETCGDWYRGYLikHKMLQGIFPKSFI 64
Cdd:cd11837    3 TALYPWRAKKENHLSFAKGDIITVLEQQEMWWFGEL--EGGEEGWFPKSYV 51

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 767938119  13 GVAIYNFQGSGAPQLSLQIGDVVRIQETCG---DWYRGyliKHKMLQGIFPKSFIHI 66
Cdd:cd11842    2 AVALYDFAGEQPGDLAFQKGDIITILKKSDsqnDWWTG---RIGGREGIFPANYVEL 55

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 767938119   14 VAIYNFQGSGAPQLSLQIGDVVRI-QETCGDWYRGYLIKHKmlQGIFP 60
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVlEKSEDGWWKGRNKGGK--EGLIP 46

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 767938119  14 VAIYNFQGSGAPQLSLQIGD-VVRIQETCGDWYRGYLIKHKMlQGIFPKSFIHI 66
Cdd:cd11923    4 VAKYNFNADTNVELSLRKGDrVVLLKQVDQNWYEGKIPGTNR-QGIFPVSYVEV 56

First 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 767938119  17 YNFQGSGAPQLSLQIGDVVRI-QETCGDWYRGyliKHKMLQGIFPKSFIHI 66
Cdd:cd11921    7 FDFQAQSPKELTLQKGDIVYIhKEVDKNWLEG---EHHGRVGIFPANYVEV 54

N-terminal Src homology 3 domain of GRB2-related adaptor protein; GRAP is a GRB-2 like adaptor protein that is highly expressed in lymphoid tissues. It acts as a negative regulator of T cell receptor (TCR)-induced lymphocyte proliferation by downregulating the signaling to the Ras/ERK pathway. It has been identified as a regulator of TGFbeta signaling in diabetic kidney tubules and may have a role in the pathogenesis of the disease. GRAP contains an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. The N-terminal SH3 domain of the related protein GRB2 binds to Sos and Sos-derived proline-rich peptides. 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 767938119  14 VAIYNFQGSGAPQLSLQIGDVVRIQETCGD--WYRGYLIKHKmlqGIFPKSFIHI 66
Cdd:cd11948    3 VALYSFQATESDELPFQKGDILKILNMEDDqnWYKAELQGRE---GYIPKNYIKV 54

First 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 767938119  11 RHGVAIYNFQGSGAPQLSLQIGDVVRI-QETCGDWYRGyliKHKMLQGIFPKSFIHI 66
Cdd:cd11919    1 RPARAKFDFKAQTLKELPLQKGDIVYIyKQIDQNWYEG---EHHGRVGIFPRSYIEL 54

N-terminal Src homology 3 domain of GRB2-related adaptor protein 2; GRAP2 is also called GADS (GRB2-related adapter downstream of Shc), GrpL, GRB2L, Mona, or GRID (Grb2-related protein with insert domain). It is expressed specifically in the hematopoietic system. It plays an important role in T cell receptor (TCR) signaling by promoting the formation of the SLP-76:LAT complex, which couples the TCR to the Ras pathway. It also have roles in antigen-receptor and tyrosine kinase mediated signaling. GRAP2 is unique from other GRB2-like adaptor proteins in that it can be regulated by caspase cleavage. It contains an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. The N-terminal SH3 domain of the related protein GRB2 binds to Sos and Sos-derived proline-rich peptides. 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 767938119  14 VAIYNFQGSGAPQLSLQIGDVVRIQETCGDWYRGYLIKHkmlQGIFPKSFIHI 66
Cdd:cd11947    3 RGKFDFTASGEDELSFKKGDVLKILSSDDIWFKAELNGE---EGYVPKNFVDI 52

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.

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gi 767938119  15 AIYNFQGSGAPQLSLQIGDVVRI-QETCGDWYRGYLikhKMLQGIFPKSFIHI 66
Cdd:cd11877    4 AKFNFEGTNEDELSFDKGDIITVtQVVEGGWWEGTL---NGKTGWFPSNYVKE 53

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

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gi 767938119  13 GVAIYNFQGSGAPQLSLQIGDVVRIQETCGD-WYRGYLIKHkmlQGIFPKSFIHI 66
Cdd:cd11782    2 ARAKYNFNADTGVELSFRKGDVITLTRRVDEnWYEGRIGGR---QGIFPVSYVQV 53

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.

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gi 767938119  15 AIYNFQGSGAPQLSLQIGDVVRI-QETCGDWYRGyliKHKMLQGIFPKSFI 64
Cdd:cd11920    5 AVYDFKAQTSKELSFKKGDTVYIlRKIDQNWYEG---EHHGRVGIFPISYV 52