C-terminal FAT-like Four helix bundle domain, also called DUF3513, of CAS (Crk-Associated Substrate) scaffolding proteins; a protein interaction module; CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes including migration, chemotaxis, apoptosis, differentiation, and progenitor cell function. They mediate the signaling of integrins at focal adhesions where they localize, and thus, regulate cell invasion and survival. Over-expression of these proteins is implicated in poor prognosis, increased metastasis, and resistance to chemotherapeutics in many cancers such as breast, lung, melanoma, and glioblastoma. CAS proteins have also been linked to the pathogenesis of inflammatory disorders, Alzheimer's, Parkinson's, and developmental defects. They share a common domain structure containing protein interaction modules that enable their scaffolding function, including an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. Vertebrates contain four CAS proteins: BCAR1 (or p130Cas), NEDD9 (or HEF1), EFS (or SIN), and CASS4 (or HEPL). The FAT-like C-terminal domain of CAS proteins binds to the C-terminal domain of NSPs (novel SH2-containing proteins) to form multidomain signaling modules that mediate cell migration and invasion.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 676 TERKIHLSKHSRLYFGALFKAISVFASSLSNGQPPEVFITQSKLVITVGQKLVDTLCSETQEKDERNEILCGSSHLCGLL 755
Cdd:cd11568     2 PARKCPLSEHCRLYFGALQKAISVFHSSLSSNQPPEVFISHSKLIIMVGQKLVDTLCQEAKEREARNEILAGSSQLCALL 81

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|..
gi 1907140587 756 KDLALATKSAVIQYPSPSALSLLQSEVERLEHHSRKFRDTLE 797
Cdd:cd11568    82 KNLALATKNAALQYPSPAALRELQDIADELAKHTQQFRAMLE 123

Serine rich Four helix bundle domain of CAS (Crk-Associated Substrate) scaffolding protein family member 4; a protein interaction module; CASS4, also called HEPL (HEF1-EFS-p130Cas-like), localizes to focal adhesions and plays a role in regulating FAK activity, focal adhesion integrity, and cell spreading. It is most abundant in blood cells and lung tissue, and is also found in high levels in leukemia and ovarian cell lines. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure containing protein interaction modules that enable their scaffolding function, including an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. CAS proteins associate with the 14-3-3 family; this interaction is regulated by integrin-mediated cell adhesion. The serine rich four helix bundle domain of BCAR1, another CAS protein, has been shown to bind 14-3-3 in a phosphorylation-dependent manner. This domain is structurally similar to other helical bundles found in cell adhesion components such as alpha-catenin, vinculin, and FAK, and may bind other proteins in addition to the 14-3-3 family.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 426 MDVDFAKETAVSLQHKVASSAAGLLLFVSRTWRFKDSLETNIHRIRRAADHVEESVREFLDFAQGVGGTACNLTDSYLQA 505
Cdd:cd11551     1 LDLEEAIETLTELQHAVSSSVASLMLFVSSKWRLREHLEANLDQIHRASDHITDSLDEFLDFARDVRGNASRLTDSNLQT 80

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1907140587 506 RIRDQLQTISSSYQTLLDAKGSLDRCNWSLEVLVTDKVQNSLDDLERFVATARIVPEDVKRFTSIVIANGKLLFKQNCE 584
Cdd:cd11551    81 RIKKQLQILEDSFQILQETAEALDNCNWSLEVLVDDKPSQMPDDLERFVMVARTIPEDIKRFVSIIIANGKLLFRKNEK 159

Crk-Associated Substrate C-terminal domain; This is a C-terminal domain found in CAS family members. The CAS (Crk-Associated Substrate) protein family is a group of scaffolding proteins that play important modulatory roles in both normal and pathological cell growth regulation. They contain an N-terminal Src homology 3 (SH3) domain pfam00018 and a substrate domain (SD). The SD contains a large number of YxxP motifs, which when phosphorylated by Src-family kinases provide canonical binding sites for proteins containing SH2 domains such as Crk, Crk-L, CRKII presumed domain is functionally uncharacterized.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 599 PQRETESYQESSPFDRQPTTEHSFELARKNRVNVCWQQSPnlqekgkptmegksnRNPDFHGMSPPPLTSPSPSGQNTER 678
Cdd:pfam12026  17 QGKEEFERQQKELLEKLPAEEQFENLIKQSKSQLEQQQQE---------------VTQPVEDPSNWTPPQSQLSPNDRQL 81

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 679 KIHLSKHSRLYFGALFKAISVFASSLSNGQPPEVFITQSKLVITVGQKLV---DTLCSETQEKDERNEILCGSSHLCGLL 755
Cdd:pfam12026  82 LLFYSEQCETHFGALLNAIDAFFSSLSNNQPPKIFVAHSKFVILSAHKLVfigDTLCRQASAADVRNRVLHCSNALCELL 161

                         170       180       190       200
                  ....*....|....*....|....*....|....*....|.
gi 1907140587 756 KDLALATKSAVIQYPSPSALSLLQSEVERLEHHSRKFRDTL 796
Cdd:pfam12026 162 KTLVLATKKAALQYPSPAAVQEMVDRVTELSHHAQQFKTVL 202

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 1907140587    7 ARALYDNHADCSDELAFSRGDILTIVEQNvpeSEGWWRC-LLHGRQGLAPANRLQ 60
Cdd:smart00326   5 VRALYDYTAQDPDELSFKKGDIITVLEKS---DDGWWKGrLGRGKEGLFPSNYVE 56

Serine rich Four helix bundle domain of CAS (Crk-Associated Substrate) scaffolding protein family member 4; a protein interaction module; CASS4, also called HEPL (HEF1-EFS-p130Cas-like), localizes to focal adhesions and plays a role in regulating FAK activity, focal adhesion integrity, and cell spreading. It is most abundant in blood cells and lung tissue, and is also found in high levels in leukemia and ovarian cell lines. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure containing protein interaction modules that enable their scaffolding function, including an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. CAS proteins associate with the 14-3-3 family; this interaction is regulated by integrin-mediated cell adhesion. The serine rich four helix bundle domain of BCAR1, another CAS protein, has been shown to bind 14-3-3 in a phosphorylation-dependent manner. This domain is structurally similar to other helical bundles found in cell adhesion components such as alpha-catenin, vinculin, and FAK, and may bind other proteins in addition to the 14-3-3 family.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 426 MDVDFAKETAVSLQHKVASSAAGLLLFVSRTWRFKDSLETNIHRIRRAADHVEESVREFLDFAQGVGGTACNLTDSYLQA 505
Cdd:cd11551     1 LDLEEAIETLTELQHAVSSSVASLMLFVSSKWRLREHLEANLDQIHRASDHITDSLDEFLDFARDVRGNASRLTDSNLQT 80

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1907140587 506 RIRDQLQTISSSYQTLLDAKGSLDRCNWSLEVLVTDKVQNSLDDLERFVATARIVPEDVKRFTSIVIANGKLLFKQNCE 584
Cdd:cd11551    81 RIKKQLQILEDSFQILQETAEALDNCNWSLEVLVDDKPSQMPDDLERFVMVARTIPEDIKRFVSIIIANGKLLFRKNEK 159

Serine rich Four helix bundle domain of CAS (Crk-Associated Substrate) scaffolding proteins; a protein interaction module; CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes including migration, chemotaxis, apoptosis, differentiation, and progenitor cell function. They mediate the signaling of integrins at focal adhesions where they localize, and thus, regulate cell invasion and survival. Over-expression of these proteins is implicated in poor prognosis, increased metastasis, and resistance to chemotherapeutics in many cancers such as breast, lung, melanoma, and glioblastoma. CAS proteins have also been linked to the pathogenesis of inflammatory disorders, Alzheimer's, Parkinson's, and developmental defects. They share a common domain structure containing protein interaction modules that enable their scaffolding function, including an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. Vertebrates contain four CAS proteins: BCAR1 (or p130Cas), NEDD9 (or HEF1), EFS (or SIN), and CASS4 (or HEPL). CAS proteins associate with the 14-3-3 family; this interaction is regulated by integrin-mediated cell adhesion. The serine rich four helix bundle domain of BCAR1 has been shown to bind 14-3-3 in a phosphorylation-dependent manner. This domain is structurally similar to other helical bundles found in cell adhesion components such as alpha-catenin, vinculin, and FAK, and may bind other proteins in addition to the 14-3-3 family.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 427 DVDFAKETAVSLQHKVASSAAGLLLFVSRTWRFKDSLETNIHRIRRAADHVEESVREFLDFAQGVGGTACNLTDSYLQAR 506
Cdd:cd11549     2 DLDAAMEKLVRLQQEVSSSVSNLLSFVSSNWRSRENLEPNIDEIKTAVDRLRTSLHEFLEFARGALANAANASDKNLQLK 81

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1907140587 507 IRDQLQTISSSYQTLLDAKGSLDRCNWSLEVLVTDKVQNSLDDLERFVATARIVPEDVKRFTSIVIANGKLLFKQNCE 584
Cdd:cd11549    82 LRRQLQPLEDSHQILSQTSQALDDCNWSLEALVDNSPSNKPDDLDRFVMCARTLPDDAKQLASFIHGNASLLFKRAPT 159

C-terminal FAT-like Four helix bundle domain, also called DUF3513, of CAS (Crk-Associated Substrate) scaffolding proteins; a protein interaction module; CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes including migration, chemotaxis, apoptosis, differentiation, and progenitor cell function. They mediate the signaling of integrins at focal adhesions where they localize, and thus, regulate cell invasion and survival. Over-expression of these proteins is implicated in poor prognosis, increased metastasis, and resistance to chemotherapeutics in many cancers such as breast, lung, melanoma, and glioblastoma. CAS proteins have also been linked to the pathogenesis of inflammatory disorders, Alzheimer's, Parkinson's, and developmental defects. They share a common domain structure containing protein interaction modules that enable their scaffolding function, including an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. Vertebrates contain four CAS proteins: BCAR1 (or p130Cas), NEDD9 (or HEF1), EFS (or SIN), and CASS4 (or HEPL). The FAT-like C-terminal domain of CAS proteins binds to the C-terminal domain of NSPs (novel SH2-containing proteins) to form multidomain signaling modules that mediate cell migration and invasion.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 677 ERKIHLSKHSRLYFGALFKAISVFASSLSNGQPPEVFITQSKLVITVGQKLV---DTLCSETQEKDERNEILCGSSHLCG 753
Cdd:cd11564     3 QLLLFYSEQCESHFGALQKAIDAFLSSVESNQPPKVFVAHSKFVILSAHKLVfigDTLCRNVQSADVRNKVLRCSNQLCE 82

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....
gi 1907140587 754 LLKDLALATKSAVIQYPSPSALSLLQSEVERLEHHSRKFRDTLE 797
Cdd:cd11564    83 ALKTVVLATKKAALQYPSVAAVQEMVDRVVELSHHAQQFKTSLG 126

Src homology 3 domain of CAS (Crk-Associated Substrate) scaffolding protein family member 4; CASS4, also called HEPL (HEF1-EFS-p130Cas-like), localizes to focal adhesions and plays a role in regulating FAK activity, focal adhesion integrity, and cell spreading. It is most abundant in blood cells and lung tissue, and is also found in high levels in leukemia and ovarian cell lines. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure that includes an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. The SH3 domain of CAS proteins binds to diverse partners including FAK, FRNK, Pyk2, PTP-PEST, DOCK180, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1907140587   5 LLARALYDNHADCSDELAFSRGDILTIVEQNVPESEGWWRCLLHGRQGLAPANRLQV 61
Cdd:cd12000     1 LLARALYDNKADCSDELAFRRGDILTVLEQNVPGSEGWWKCLLHGRQGLAPANRLQL 57

Src homology 3 domain of CAS (Crk-Associated Substrate) scaffolding proteins; CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes including migration, chemotaxis, apoptosis, differentiation, and progenitor cell function. They mediate the signaling of integrins at focal adhesions where they localize, and thus, regulate cell invasion and survival. Over-expression of these proteins is implicated in poor prognosis, increased metastasis, and resistance to chemotherapeutics in many cancers such as breast, lung, melanoma, and glioblastoma. CAS proteins have also been linked to the pathogenesis of inflammatory disorders, Alzheimer's, Parkinson's, and developmental defects. They share a common domain structure that includes an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. Vertebrates contain four CAS proteins: BCAR1 (or p130Cas), NEDD9 (or HEF1), EFS (or SIN), and CASS4 (or HEPL). The SH3 domain of CAS proteins binds to diverse partners including FAK, FRNK, Pyk2, PTP-PEST, DOCK180, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1907140587   6 LARALYDNHADCSDELAFSRGDILTIVEQNVPESEGWWRCLLHGRQGLAPANRLQV 61
Cdd:cd11844     1 LARALYDNVAESPDELAFRRGDILTVLEQNTAGLEGWWLCSLRGRQGIAPGNRLKL 56

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

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1907140587   6 LARALYDNHADCSDELAFSRGDILTIVEQNVPESEGWWRCLLHGRQGLAPANRLQVLRETP 66
Cdd:cd12003     2 LAKALYDNAAESPEELSFRRGDVLMVLKREHGSLPGWWLCSLHGQQGIAPANRLRLLPTAP 62

Src homology 3 domain of the CAS (Crk-Associated Substrate) scaffolding protein family member, Breast Cancer Anti-estrogen Resistance 1; BCAR1, also called p130cas or CASS1, is the founding member of the CAS family of scaffolding proteins and was originally identified through its ability to associate with Crk. The name BCAR1 was designated because the human gene was identified in a screen for genes that promote resistance to tamoxifen. It is widely expressed and its deletion is lethal in mice. It plays a role in regulating cell motility, survival, proliferation, transformation, cancer progression, and bacterial pathogenesis. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure that includes an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain. The SH3 domain of CAS proteins binds to diverse partners including FAK, FRNK, Pyk2, PTP-PEST, DOCK180, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1907140587   5 LLARALYDNHADCSDELAFSRGDILTIVEQNVPESEGWWRCLLHGRQGLAPANRLQVL 62
Cdd:cd12001     3 VLAKALYDNVAESPDELSFRKGDIMTVLERDTQGLDGWWLCSLHGRQGIVPGNRLKIL 60

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 1907140587    7 ARALYDNHADCSDELAFSRGDILTIVEQNvpeSEGWWRC-LLHGRQGLAPANRLQ 60
Cdd:smart00326   5 VRALYDYTAQDPDELSFKKGDIITVLEKS---DDGWWKGrLGRGKEGLFPSNYVE 56

C-terminal FAT-like Four helix bundle domain, also called DUF3513, of CAS (Crk-Associated Substrate) scaffolding protein, Embryonal Fyn-associated Substrate; a protein interaction module; EFS is also called HEFS, CASS3 (CAS scaffolding protein family member 3) or SIN (Src-interacting protein). It was identified based on interactions with the Src kinases, Fyn and Yes. It plays a role in thymocyte development and acts as a negative regulator of T cell proliferation. CAS proteins function as molecular scaffolds to regulate protein complexes that are involved in many cellular processes. They share a common domain structure containing protein interaction modules that enable their scaffolding function, including an N-terminal SH3 domain, an unstructured substrate domain that contains many YxxP motifs, a serine-rich four-helix bundle, and a FAT-like C-terminal domain, which binds to the C-terminal domain of NSPs (novel SH2-containing proteins) to form multidomain signaling modules that mediate cell migration and invasion.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907140587 683 SKHSRLYFGALFKAISVFASSLSNGQPPEVFITQSKLVITVGQKLV---DTLCSETQEKDERNEILCGSSHLCGLLKDLA 759
Cdd:cd11571    10 AGQCQSHYSTLLAAVAALLSSTQANQPPRVFVPHGKRLIVAAHKLVfvgDTLGRLASSAPLRARVATAGGALCQALKAVV 89

                          90       100       110
                  ....*....|....*....|....*....|...
gi 1907140587 760 LATKSAVIQYPSPSALSLLQSEVERLEHHSRKF 792
Cdd:cd11571    90 LATKGAALGYPSPPAAQEMAQCVADLSGQALQF 122

Src Homology 3 domain of metazoan osteoclast stimulating factor 1; OSTF1, also named OSF or SH3P2, is a signaling protein containing SH3 and ankyrin-repeat domains. It acts through a Src-related pathway to enhance the formation of osteoclasts and bone resorption. It also acts as a negative regulator of cell motility. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNVPeseGWWRCLLHGRQGLAPAN 57
Cdd:cd11772     3 RALYDYEAQHPDELSFEEGDLLYISDKSDP---NWWKATCGGKTGLIPSN 49

Variant SH3 domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1907140587   9 ALYDNHADCSDELAFSRGDILTIVEQnvpESEGWWRCLLHGRQGLAPANRLQ 60
Cdd:pfam14604   1 ALYPYEPKDDDELSLQRGDVITVIEE---SEDGWWEGINTGRTGLVPANYVE 49

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 1907140587   6 LARALYDNHADCSDELAFSRGDILTIVEQNVPEsegWWRCLLHGRQGLAPANRLQV 61
Cdd:cd11805     1 RVQALYDFNPQEPGELEFRRGDIITVLDSSDPD---WWKGELRGRVGIFPANYVQP 53

Src Homology 3 domain of Sorting Nexin 9 and similar proteins; Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. This subfamily consists of SH3 domain containing SNXs including SNX9, SNX18, SNX33, and similar proteins. SNX9 is localized to plasma membrane endocytic sites and acts primarily in clathrin-mediated endocytosis, while SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1907140587   6 LARALYDNHADCSDELAFSRGDILTIVEQNVpeSEGWWRCL-LHGRQGLAPANRLQV 61
Cdd:cd11763     1 KVRALYDFDSQPSGELSLRAGEVLTITRQDV--GDGWLEGRnSRGEVGLFPSSYVEI 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 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEQnvpESEGWWRCLLHGRQGLAPANRLQVL 62
Cdd:cd12073     3 AVALYDYQGEGDDEISFDPQETITDIEM---VDEGWWKGTCHGHRGLFPANYVELL 55

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        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNvpeSEGWWRCLLHGRQGLAPAN 57
Cdd:cd11826     3 VALYDYTADKDDELSFQEGDIIYVTKKN---DDGWYEGVLNGVTGLFPGN 49

Fifth 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.

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEqnvPESEGWWRCLLHGRQGLAPAN 57
Cdd:cd11818     2 ARALYDFTGENEDELSFKAGDIITELE---SIDEEWMSGELRGKSGIFPKN 49

Src Homology 3 (SH3) domain of Inhibitor of ASPP protein (iASPP); iASPP, also called RelA-associated inhibitor (RAI), is an oncoprotein that inhibits the apoptotic transactivation potential of p53. It is upregulated in human breast cancers expressing wild-type p53, in acute leukemias regardless of the p53 mutation status, as well as in ovarian cancer where it is associated with poor patient outcome and chemoresistance. iASPP is also a binding partner and negative regulator of p65RelA, which promotes cell proliferation and inhibits apoptosis; p65RelA has the opposite effect on cell growth compared to the p53 family. It contains a proline-rich region, four ankyrin (ANK) repeats, and an SH3 domain at its C-terminal half. The SH3 domain and the ANK repeats of iASPP contribute to the p53 binding site; they bind to the DNA binding domain of p53. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1907140587   9 ALYDNHADCSDELAFSRGDILTIVEQNvPESEGWWRCLLHGRQGLAPAN 57
Cdd:cd11952     5 ALWDYSAEFPDELSFKEGDMVTVLRKD-GEGTDWWWASLCGREGYVPRN 52

Src homology 3 domain of Protein kinase C and Casein kinase Substrate in Neurons (PACSIN) proteins; PACSINs, also called Synaptic dynamin-associated proteins (Syndapins), act as regulators of cytoskeletal and membrane dynamics. They bind both dynamin and Wiskott-Aldrich syndrome protein (WASP), and may provide direct links between the actin cytoskeletal machinery through WASP and dynamin-dependent endocytosis. Vetebrates harbor three isoforms with distinct expression patterns and specific functions. PACSINs contain an N-terminal F-BAR domain and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNvpESEGWWRCLLHGRQGLAPAN 57
Cdd:cd11843     3 RALYDYEGQESDELSFKAGDILTKLEEE--DEQGWCKGRLDGRVGLYPAN 50

Src homology 3 domains of the p47phox subunit of NADPH oxidase and similar domains; This family is composed of the tandem SH3 domains of p47phox subunit of NADPH oxidase and Nox Organizing protein 1 (NoxO1), the four SH3 domains of Tks4 (Tyr kinase substrate with four SH3 domains), the five SH3 domains of Tks5, the SH3 domain of obscurin, Myosin-I, and similar domains. Most members of this group also contain Phox homology (PX) domains, except for obscurin and Myosin-I. p47phox and NoxO1 are regulators of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) and nonphagocytic NADPH oxidase Nox1, respectively. They play roles in the activation of their respective NADPH oxidase, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Tks proteins are Src substrates and scaffolding proteins that play important roles in the formation of podosomes and invadopodia, the dynamic actin-rich structures that are related to cell migration and cancer cell invasion. Obscurin is a giant muscle protein that plays important roles in the organization and assembly of the myofibril and the sarcoplasmic reticulum. Type I myosins (Myosin-I) are actin-dependent motors in endocytic actin structures and actin patches. They play roles in membrane traffic in endocytic and secretory pathways, cell motility, and mechanosensing. Myosin-I contains an N-terminal actin-activated ATPase, a phospholipid-binding TH1 (tail homology 1) domain, and a C-terminal extension which includes an F-actin-binding TH2 domain, an SH3 domain, and an acidic peptide that participates in activating the Arp2/3complex. The SH3 domain of myosin-I is required for myosin-I-induced actin polymerization. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNvpeSEGWWRCLLHGRQGLAPANRL 59
Cdd:cd11856     3 VAIADYEAQGDDEISLQEGEVVEVLEKN---DSGWWYVRKGDKEGWVPASYL 51

Src Homology 3 domain of SH3 domain-containing protein 21 (SH3D21) and similar proteins; N-terminal SH3 domain of the uncharacterized protein SH3 domain-containing protein 21, and similar uncharacterized domains, it belongs to the CD2AP-like_3 subfamily of proteins. The CD2AP-like_3 subfamily is composed of the third SH3 domain (SH3C) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3C of both proteins have been shown to bind to ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNVpESEGWWRCLLHGRQGLAPAN 57
Cdd:cd12142     3 RVLFDYNPVAPDELALKKGDVIEVISKET-EDEGWWEGELNGRRGFFPDN 51

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.

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVeqNVPESEGWWRCLLHGRQGLAPANRLQV 61
Cdd:cd11948     2 AVALYSFQATESDELPFQKGDILKIL--NMEDDQNWYKAELQGREGYIPKNYIKV 54

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

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEQNVPEsegWWRCLLHGRQGLAPAN 57
Cdd:cd11950     2 VRALYDFEALEDDELGFNSGDVIEVLDSSNPS---WWKGRLHGKLGLFPAN 49

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

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEQNVPEsegWWRCLLHGRQGLAPAN 57
Cdd:cd11817     2 AVALYDFTGETEEDLSFQRGDRILVTEHLDAE---WSRGRLNGREGIFPRA 49

Src homology 3 domain of Signal Transducing Adaptor Molecules; STAMs were discovered as proteins that are highly phosphorylated following cytokine and growth factor stimulation. They function in cytokine signaling and surface receptor degradation, as well as regulate Golgi morphology. They associate with many proteins including Jak2 and Jak3 tyrosine kinases, Hrs, AMSH, and UBPY. STAM adaptor proteins contain VHS (Vps27, Hrs, STAM homology), ubiquitin interacting (UIM), and SH3 domains. There are two vertebrate STAMs, STAM1 and STAM2, which may be functionally redundant; vertebrate STAMs contain ITAM motifs. They are part of the endosomal sorting complex required for transport (ESCRT-0). STAM2 deficiency in mice did not cause any obvious abnormality, while STAM1 deficiency resulted in growth retardation. Loss of both STAM1 and STAM2 in mice proved lethal, indicating that STAMs are important for embryonic development. 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 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNVPEsegWWRCLLHGRQGLAPAN 57
Cdd:cd11820     4 RALYDFEAAEDNELTFKAGEIITVLDDSDPN---WWKGSNHRGEGLFPAN 50

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

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEQNvpESEGWWRCLLHGRQGLAPAN 57
Cdd:cd11882     2 ARALYACKAEDESELSFEPGQIITNVQPS--DEPGWLEGTLNGRTGLIPEN 50

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

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEQnvpESEGWWRCLLHGRQGLAPANRLQVL 62
Cdd:pfam07653   2 GRVIFDYVGTDKNGLTLKKGDVVKVLGK---DNDGWWEGETGGRVGLVPSTAVEEI 54

Third N-terminal Src homology 3 domain of Dynamin Binding Protein, also called Tuba; DNMBP or Tuba is a cdc42-specific guanine nucleotide exchange factor (GEF) that contains four N-terminal SH3 domains, a central RhoGEF [or Dbl homology (DH)] domain followed by a Bin/Amphiphysin/Rvs (BAR) domain, and two C-terminal SH3 domains. It provides a functional link between dynamin and key regulatory proteins of the actin cytoskeleton. It plays an important role in regulating cell junction configuration. The four N-terminal SH3 domains of DNMBP binds the GTPase dynamin, which plays an important role in the fission of endocytic vesicles. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEqnVPESeGWWRCLLHGRQGLAPAN 57
Cdd:cd11796     2 ARVLQDLSAQLDEELDLREGDVVTITG--ILDK-GWFRGELNGRRGIFPEG 49

Src Homology 3 domain of Mixed Lineage Kinases 1, 2, and 3; MLKs 1, 2, and 3 are Serine/Threonine Kinases (STKs), catalyzing the transfer of the gamma-phosphoryl group from ATP to S/T residues on protein substrates. MLKs act as mitogen-activated protein kinase kinase kinases (MAP3Ks, MKKKs, MAPKKKs), which phosphorylate and activate MAPK kinases (MAPKKs or MKKs or MAP2Ks), which in turn phosphorylate and activate MAPKs during signaling cascades that are important in mediating cellular responses to extracellular signals. MLKs play roles in immunity and inflammation, as well as in cell death, proliferation, and cell cycle regulation. Little is known about the specific function of MLK1, also called MAP3K9. It is capable of activating the c-Jun N-terminal kinase pathway. Mice lacking both MLK1 and MLK2 are viable, fertile, and have normal life spans. MLK2, also called MAP3K10, is abundant in brain, skeletal muscle, and testis. It functions upstream of the MAPK, c-Jun N-terminal kinase. It binds hippocalcin, a calcium-sensor protein that protects neurons against calcium-induced cell death. Both MLK2 and hippocalcin may be associated with the pathogenesis of Parkinson's disease. MLK3, also called MAP3K11, is highly expressed in breast cancer cells and its signaling through c-Jun N-terminal kinase has been implicated in the migration, invasion, and malignancy of cancer cells. It also functions as a negative regulator of Inhibitor of Nuclear Factor-KappaB Kinase (IKK) and thus, impacts inflammation and immunity. MLKs contain an SH3 domain, a catalytic kinase domain, a leucine zipper, a proline-rich region, and a CRIB domain that mediates binding to GTP-bound Cdc42 and Rac. 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 1907140587   2 FWTllarALYDNHADCSDELAFSRGDILTIVEQN--VPESEGWWRCLLHGRQGLAPAN 57
Cdd:cd12059     1 VWT----AVFDYEASAEDELTLRRGDRVEVLSKDsaVSGDEGWWTGKINDRVGIFPSN 54

Src homology 3 domain of Protein kinase C and Casein kinase Substrate in Neurons 1 (PACSIN1) and PACSIN 2; PACSIN 1 or Syndapin I (Synaptic dynamin-associated protein I) is expressed specifically in the brain and is localized in neurites and synaptic boutons. It binds the brain-specific proteins dynamin I, synaptojanin, synapsin I, and neural Wiskott-Aldrich syndrome protein (nWASP), and functions as a link between the cytoskeletal machinery and synaptic vesicle endocytosis. PACSIN 1 interacts with huntingtin and may be implicated in the neuropathology of Huntington's disease. PACSIN 2 or Syndapin II is expressed ubiquitously and is involved in the regulation of tubulin polymerization. It associates with Golgi membranes and forms a complex with dynamin II which is crucial in promoting vesicle formation from the trans-Golgi network. PACSINs act as regulators of cytoskeletal and membrane dynamics. Vetebrates harbor three isoforms with distinct expression patterns and specific functions. PACSINs contain an N-terminal F-BAR domain and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNvpESEGWWRCLL-HGRQGLAPANRLQ 60
Cdd:cd11998     4 RALYDYDGQEQDELSFKAGDELTKLEDE--DEQGWCKGRLdSGQVGLYPANYVE 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.

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gi 1907140587   7 ARALYDNHADCSDELAFSRGDILTIVEQnvpESEGWWRCLLHGRQGLAPAN 57
Cdd:cd11873     2 VIVEFDYDAEEPDELTLKVGDIITNVKK---MEEGWWEGTLNGKRGMFPDN 49

Src Homology 3 domain of beta-Pak Interactive eXchange factor; Beta-PIX, also called Rho guanine nucleotide exchange factor 7 (ARHGEF7) or Cool (Cloned out of Library)-1, activates small GTPases by exchanging bound GDP for free GTP. It acts as a GEF for both Cdc42 and Rac 1, and plays important 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 1907140587   6 LARALYDNHADCSDELAFSRGDILTIVEQnvpESEGWWRCLLHGRQGLAPAN 57
Cdd:cd12061     1 VVRAKFNFQQTNEDELSFSKGDVIHVTRV---EEGGWWEGTHNGRTGWFPSN 49

Src homology 3 domain of Src kinase-like Protein Tyrosine Kinases; Src subfamily members include Src, Lck, Hck, Blk, Lyn, Fgr, Fyn, Yrk, Yes, and Brk. Src (or c-Src) proteins are cytoplasmic (or non-receptor) PTKs which are anchored to the plasma membrane. They contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). However, Brk lacks the N-terminal myristoylation sites. Src proteins are involved in signaling pathways that regulate cytokine and growth factor responses, cytoskeleton dynamics, cell proliferation, survival, and differentiation. They were identified as the first proto-oncogene products, and they regulate cell adhesion, invasion, and motility in cancer cells, and tumor vasculature, contributing to cancer progression and metastasis. Src kinases are overexpressed in a variety of human cancers, making them attractive targets for therapy. They are also implicated in acute inflammatory responses and osteoclast function. Src, Fyn, Yes, and Yrk are widely expressed, while Blk, Lck, Hck, Fgr, Lyn, and Brk show a limited expression pattern. This subfamily also includes Drosophila Src42A, Src oncogene at 42A (also known as Dsrc41) which accumulates at sites of cell-cell or cell-matrix adhesion, and participates in Drosphila development and wound healing. It has been shown to promote tube elongation in the tracheal system, is essential for proper cell-cell matching during dorsal closure, and regulates cell-cell contacts in developing Drosophila eyes. The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1907140587   8 RALYDNHADCSDELAFSRGDILTIVEQNVPEsegWW--RCLLHGRQGLAPAN 57
Cdd:cd11845     3 VALYDYEARTDDDLSFKKGDRLQILDDSDGD---WWlaRHLSTGKEGYIPSN 51