First Src Homology 3 domain of Bzz1 and similar domains; Bzz1 (or Bzz1p) is a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Together with other proteins, it induces membrane scission in yeast. Bzz1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. This model represents the first 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 2008376973 515 KAKVLYSYEASGEFEVSITEDTTVQVVEPDDGSGWVKVVNERGAEGLVPATYVEI 569
Cdd:cd11912     1 TAKVLYDYTASGDDEVSISEGEEVTVLEPDDGSGWTKVRNGSGEEGLVPTSYIEI 55

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 2008376973  590 AKLVKALYSYEAQGDDELSLKEGMTYELTpngESAGDGWWEGTDSSGRKGIFPSNYVE 647
Cdd:smart00326   2 GPQVRALYDYTAQDPDELSFKKGDIITVL---EKSDDGWWKGRLGRGKEGLFPSNYVE 56

First Src Homology 3 domain of Bzz1 and similar domains; Bzz1 (or Bzz1p) is a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Together with other proteins, it induces membrane scission in yeast. Bzz1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. This model represents the first 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 2008376973 515 KAKVLYSYEASGEFEVSITEDTTVQVVEPDDGSGWVKVVNERGAEGLVPATYVEI 569
Cdd:cd11912     1 TAKVLYDYTASGDDEVSISEGEEVTVLEPDDGSGWTKVRNGSGEEGLVPTSYIEI 55

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 2008376973  590 AKLVKALYSYEAQGDDELSLKEGMTYELTpngESAGDGWWEGTDSSGRKGIFPSNYVE 647
Cdd:smart00326   2 GPQVRALYDYTAQDPDELSFKKGDIITVL---EKSDDGWWKGRLGRGKEGLFPSNYVE 56

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Cdc42-Interacting Protein 4 and similar proteins; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. This subfamily is composed of Cdc42-Interacting Protein 4 (CIP4), Formin Binding Protein 17 (FBP17), FormiN Binding Protein 1-Like (FNBP1L), and similar proteins. CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. CIP4 and FBP17 bind to the Fas ligand and may be implicated in the inflammatory response. CIP4 may also play a role in phagocytosis. Members of this subfamily typically contain an N-terminal F-BAR domain and a C-terminal SH3 domain. In addition, some members such as FNBP1L contain a central Cdc42-binding HR1 domain. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2008376973  13 KELPDQVPALNATLTHQITLLVDVRELIKERVALEKEYAIRLSAIAKKAEEKRArhmthavlgeecskawSDADVRSSTL 92
Cdd:cd07653     1 TELWDQFDNLEKHTQKGIDFLERYGKFVKERAAIEQEYAKKLRKLVKKYLPKKK----------------EEDEYSFSSV 64

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2008376973  93 dKAFTALINSYENTASDHDSFASALSADVADALKLLERSKDESRKKQMAFFAKLVAERD--------------RIYGERL 158
Cdd:cd07653    65 -KAFRSILNEVNDIAGQHELIAENLNSNVCKELKTLISELRQERKKHLSEGSKLQQKLEssikqlekskkayeKAFKEAE 143

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2008376973 159 KAKQK-DRAADDKHADRA----AKQLEQQKVEMQNR-KNAYLIQITVANSAKDRFYDDELPLLEDQFQAhhADTMR--RM 230
Cdd:cd07653   144 KAKQKyEKADADMNLTKAdvekAKANANLKTQAAEEaKNEYAAQLQKFNKEQRQHYSTDLPQIFDKLQE--LDEKRinRT 221

                  ....*..
gi 2008376973 231 TRLLLHS 237
Cdd:cd07653   222 VELLLQA 228

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 2008376973  512 SATKAKVLYSYEASGEFEVSITEDTTVQVVEPDDGsGWVKVVNERGAEGLVPATYVE 568
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSFKKGDIITVLEKSDD-GWWKGRLGRGKEGLFPSNYVE 56

Protein kinase C conserved region 1 (C1) domains (Cysteine-rich domains); Some bind phorbol esters and diacylglycerol. Some bind RasGTP. Zinc-binding domains.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|
gi 2008376973  398 HEFKSASFSIPSPCGYCKSNIWGLSKPGKTCRNCGISVHTRCELKMPAEC 447
Cdd:smart00109   1 HKHVFRTFTKPTFCCVCRKSIWGSFKQGLRCSECKVKCHKKCADKVPKAC 50

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 2008376973 517 KVLYSYEASGEFEVSITEDTTVQVVEpDDGSGWVKVVNERGAEGLVPA 564
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVLE-KSEDGWWKGRNKGGKEGLIPS 47

Uncharacterized conserved protein YgiM, contains N-terminal SH3 domain, DUF1202 family [General function prediction only];

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 2008376973 531 SITEDTTVQVVEPDDGsgWVKVVNERGAEGLVPATYVEIVAPA-------LNKRRAP 580
Cdd:COG3103    29 TLPKGEKVTVLGRSGG--WYKVRYSNGKTGWVSSRYLTVTPSArerlpdeLNLRAGP 83

First Src Homology 3 domain of Bzz1 and similar domains; Bzz1 (or Bzz1p) is a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Together with other proteins, it induces membrane scission in yeast. Bzz1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. This model represents the first 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 2008376973 515 KAKVLYSYEASGEFEVSITEDTTVQVVEPDDGSGWVKVVNERGAEGLVPATYVEI 569
Cdd:cd11912     1 TAKVLYDYTASGDDEVSISEGEEVTVLEPDDGSGWTKVRNGSGEEGLVPTSYIEI 55

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 2008376973  590 AKLVKALYSYEAQGDDELSLKEGMTYELTpngESAGDGWWEGTDSSGRKGIFPSNYVE 647
Cdd:smart00326   2 GPQVRALYDYTAQDPDELSFKKGDIITVL---EKSDDGWWKGRLGRGKEGLFPSNYVE 56

Src homology 3 domain of Cortactin and related proteins; This subfamily includes cortactin, Abp1 (actin-binding protein 1), hematopoietic lineage cell-specific protein 1 (HS1), and similar proteins. These proteins are involved in regulating actin dynamics through direct or indirect interaction with the Arp2/3 complex, which is required to initiate actin polymerization. They all contain at least one C-terminal SH3 domain. Cortactin and HS1 bind Arp2/3 and actin through an N-terminal region that contains an acidic domain and several copies of a repeat domain found in cortactin and HS1. Abp1 binds actin via an N-terminal actin-depolymerizing factor (ADF) homology domain. Yeast Abp1 binds Arp2/3 directly through two acidic domains. Mammalian Abp1 does not directly interact with Arp2/3; instead, it regulates actin dynamics indirectly by interacting with dynamin and WASP family proteins. The C-terminal region of these proteins acts as an adaptor or scaffold that can connect membrane trafficking and signaling proteins that bind the SH3 domain within the actin network. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2008376973 594 KALYSYEAQGDDELSLKEGmtyELTPNGESAGDGWWEGTDSSGRKGIFPSNYVE 647
Cdd:cd11819     3 KALYDYQAAEDNEISFVEG---DIITQIEQIDEGWWLGVNAKGQKGLFPANYVE 53

protein kinase C conserved region 1 (C1 domain) superfamily; The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains. It contains the motif HX12CX2CXnCX2CX4HX2CX7C, where C and H are cysteine and histidine, respectively; X represents other residues; and n is either 13 or 14. C1 has a globular fold with two separate Zn(2+)-binding sites. It was originally discovered as lipid-binding modules in protein kinase C (PKC) isoforms. C1 domains that bind and respond to phorbol esters (PE) and diacylglycerol (DAG) are referred to as typical, and those that do not respond to PE and DAG are deemed atypical. A C1 domain may also be referred to as PKC or non-PKC C1, based on the parent protein's activity. Most C1 domain-containing non-PKC proteins act as lipid kinases and scaffolds, except PKD which acts as a protein kinase. PKC C1 domains play roles in membrane translocation and activation of the enzyme.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 2008376973 398 HEFKSASFSIPSPCGYCKSNIWGLSKPGKTCRNCGISVHTRCELKMPAEC 447
Cdd:cd00029     1 HRFVPTTFSSPTFCDVCGKLIWGLFKQGLKCSDCGLVCHKKCLDKAPSPC 50

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 2008376973 593 VKALYSYEAQGDDELSLKEG-MTYELTPNgesaGDGWWEGTdSSGRKGIFPSNYVE 647
Cdd:cd11826     2 VVALYDYTADKDDELSFQEGdIIYVTKKN----DDGWYEGV-LNGVTGLFPGNYVE 52

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 2008376973 592 LVKALYSYEAQGDDELSLKEGMtyELTPNGESAGDGWWEGTDSSGRKGIFPSNYVE 647
Cdd:cd11763     1 KVRALYDFDSQPSGELSLRAGE--VLTITRQDVGDGWLEGRNSRGEVGLFPSSYVE 54

Src Homology 3 domain of Cdc42-Interacting Protein 4; This subfamily is composed of Cdc42-Interacting Protein 4 (CIP4), Formin Binding Protein 17 (FBP17), FormiN Binding Protein 1-Like (FNBP1L), and similar proteins. CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. CIP4 and FBP17 bind to the Fas ligand and may be implicated in the inflammatory response. CIP4 may also play a role in phagocytosis. It functions downstream of Cdc42 in PDGF-dependent actin reorganization and cell migration, and also regulates the activity of PDGFRbeta. It uses Src as a substrate in regulating the invasiveness of breast tumor cells. CIP4 may also play a role in the pathogenesis of Huntington's disease. Members of this subfamily typically contain an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain, a central Cdc42-binding HR1 domain, and a C-terminal SH3 domain. The SH3 domain of CIP4 associates with Gapex-5, a Rab31 GEF. 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 2008376973 515 KAKVLYSYEASGEFEVSITEDTTVQVVEPDDGSGWVKVVNERGAEGLVPATYVEI 569
Cdd:cd11911     1 TCTALYDFDGTSEGTLSMEEGEILLVLEEDGGDGWTRVRKNNGDEGYVPTSYIEV 55

protein kinase C conserved region 1 (C1 domain) found in tensin-2 like (TNS2-like) proteins; The TNS2-like group includes TNS2, and variants of TNS1 and TNS3. Tensin-2 (TNS2), also called C1 domain-containing phosphatase and tensin (C1-TEN), or tensin-like C1 domain-containing phosphatase (TENC1), is an essential component for the maintenance of glomerular basement membrane (GBM) structures. It regulates cell motility and proliferation. It may have phosphatase activity. TNS2 reduces AKT1 phosphorylation, lowers AKT1 kinase activity and interferes with AKT1 signaling. Tensin-1 (TNS1) plays a role in fibrillar adhesion formation. It may be involved in cell migration, cartilage development and in linking signal transduction pathways to the cytoskeleton. Tensin-3 (TNS3), also called tensin-like SH2 domain-containing protein 1 (TENS1), or tumor endothelial marker 6 (TEM6), may play a role in actin remodeling. It is involved in the dissociation of the integrin-tensin-actin complex. Typical TNS1 and TNS3 do not contain C1 domains, but some isoforms/variants do. Members of this family contain an N-terminal region with a zinc finger (C1 domain), a protein tyrosine phosphatase (PTP)-like domain and a protein kinase 2 (C2) domain, and a C-terminal region with SH2 and pTyr binding (PTB) domains. This model corresponds to C1 domain. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.

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                  ....*....|....*....|....*....|....*....|....*....|...
gi 2008376973 396 KPHEFKSASFSIPSPCGYCKSNIWGlskPGKTCRNCGISVHTRCELKMPAECG 448
Cdd:cd20826     1 KSHSFKEKSFRKPRTCDVCKQIIWN---EGSSCRVCKYACHRKCEPKVTAACS 50

Src homology 3 domain of Nitric Oxide Synthase TRaffic INducer; Nostrin is expressed in endothelial and epithelial cells and is involved in the regulation, trafficking and targeting of endothelial NOS (eNOS). It facilitates the endocytosis of eNOS by coordinating the functions of dynamin and the Wiskott-Aldrich syndrome protein (WASP). Increased expression of Nostrin may be correlated to preeclampsia. Nostrin contains an N-terminal F-BAR domain and a C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 2008376973 594 KALYSYEAQGDDELSLKEGMTYELTPNGEsagDGWWEGtDSSGRKGIFPSNYVE 647
Cdd:cd11823     3 KALYSYTANREDELSLQPGDIIEVHEKQD---DGWWLG-ELNGKKGIFPATYVE 52

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 2008376973 515 KAKVLYSYEASGEFEVSITEDTTVQVVEPDDGSGWVKVVNERGAEGLVPATYVEI 569
Cdd:cd11763     1 KVRALYDFDSQPSGELSLRAGEVLTITRQDVGDGWLEGRNSRGEVGLFPSSYVEI 55

second protein kinase C conserved region 1 (C1 domain) found in classical (or conventional) protein kinase C (cPKC), novel protein kinase C (nPKC), and similar proteins; PKCs are classified into three groups (classical, atypical, and novel) depending on their mode of activation and the structural characteristics of their regulatory domain. PKCs undergo three phosphorylations in order to take mature forms. In addition, cPKCs depend on calcium, DAG (1,2-diacylglycerol), and in most cases, phosphatidylserine (PS) for activation. nPKCs are calcium-independent, but require DAG and PS for activity, while atypical PKCs (aPKCs) only require PS. PKCs phosphorylate and modify the activities of a wide variety of cellular proteins including receptors, enzymes, cytoskeletal proteins, transcription factors, and other kinases. They play a central role in signal transduction pathways that regulate cell migration and polarity, proliferation, differentiation, and apoptosis. This family includes classical PKCs (cPKCs) and novel PKCs (nPKCs). There are four cPKC isoforms (named alpha, betaI, betaII, and gamma) and four nPKC isoforms (delta, epsilon, eta, and theta). Members of this family contain two copies of C1 domain. This model corresponds to the second one. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.

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gi 2008376973 398 HEFKSASFSIPSPCGYCKSNIWGLSKPGKTCRNCGISVHTRCELKMPAEC 447
Cdd:cd20793     1 HKFKVHTYYSPTFCDHCGSLLYGLVRQGLKCKDCGMNVHHRCKENVPHLC 50

Second Src Homology 3 domain (SH3B) of CD2-associated protein and similar proteins; This subfamily is composed of the second SH3 domain (SH3B) 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. SH3B of both proteins have been shown to bind to Cbl. In the case of CD2AP, its SH3B binds to Cbl at a site distinct from the c-Cbl/SH3A binding site. The CIN85 SH3B also binds 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 2008376973 594 KALYSYEAQGDDELSLKEGMTYELtpNGESAgDGWWEGTdSSGRKGIFPSNYVE 647
Cdd:cd11874     3 KVLFSYTPQNEDELELKVGDTIEV--LGEVE-EGWWEGK-LNGKVGVFPSNFVK 52

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.

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                   ....*....|....*....|....*....|....*....|....*....|....*..
gi 2008376973  512 SATKAKVLYSYEASGEFEVSITEDTTVQVVEPDDGsGWVKVVNERGAEGLVPATYVE 568
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSFKKGDIITVLEKSDD-GWWKGRLGRGKEGLFPSNYVE 56

Src Homology 3 domain of Mixed Lineage Kinases; MLKs 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. Mammals have four MLKs (MLK1-4), mostly conserved in vertebrates, which 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 2008376973 595 ALYSYEAQGDDELSLKEGMTYE-LTPNGESAGD-GWWEGTDSSgRKGIFPSNYV 646
Cdd:cd11876     4 ALFDYDARGEDELTLRRGQPVEvLSKDAAVSGDeGWWTGKIGD-KVGIFPSNYV 56

Src Homology 3 domain of Mixed Lineage Kinase 4; MLK4 is a Serine/Threonine Kinase (STK), 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. The specific function of MLK4 is yet to be determined. Mutations in the kinase domain of MLK4 have been detected in colorectal cancers. MLK4 contains 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 2008376973 592 LVKALYSYEAQGDDELSLKEGMTYE-LTPNGESAGD-GWWEGTDSSgRKGIFPSNYVER 648
Cdd:cd12058     1 LWTALYDYEASGEDELSLRRGDVVEvLSQDAAVSGDdGWWAGKIRH-RLGIFPANYVTR 58

Src homology 3 domain of eumetazoan Actin-binding protein 1; Abp1, also called drebrin-like protein, is an adaptor protein that functions in receptor-mediated endocytosis and vesicle trafficking. It contains an N-terminal actin-binding module, the actin-depolymerizing factor (ADF) homology domain, a helical domain, and a C-terminal SH3 domain. Mammalian Abp1, unlike yeast Abp1, does not contain an acidic domain that interacts with the Arp2/3 complex. It regulates actin dynamics indirectly by interacting with dynamin and WASP family proteins. Abp1 deficiency causes abnormal organ structure and function of the spleen, heart, and lung of mice. 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 2008376973 593 VKALYSYEAQGDDELSLKEGmtyELTPNGESAGDGWWEGTDSSGRKGIFPSNYVE 647
Cdd:cd11960     2 ARALYDYQAADDTEISFDPG---DIITDIEQIDEGWWRGTGPDGTYGLFPANYVE 53

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 2008376973 594 KALYSYEAQGDDELSLKEGMTYELTpngESAGDGWWEGTDSSGRKGIFPS 643
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVL---EKSEDGWWKGRNKGGKEGLIPS 47

Second Src Homology 3 domain of Nck adaptor proteins; Nck adaptor proteins regulate actin cytoskeleton dynamics by linking proline-rich effector molecules to protein tyrosine kinases and phosphorylated signaling intermediates. They contain three SH3 domains and a C-terminal SH2 domain. They function downstream of the PDGFbeta receptor and are involved in Rho GTPase signaling and actin dynamics. Vertebrates contain two Nck adaptor proteins: Nck1 (also called Nckalpha) and Nck2 (also called Nckbeta or Growth factor receptor-bound protein 4, Grb4), which show partly overlapping functions but also bind distinct targets. Their SH3 domains are involved in recruiting downstream effector molecules, such as the N-WASP/Arp2/3 complex, which when activated induces actin polymerization that results in the production of pedestals, or protrusions of the plasma membrane. The second SH3 domain of Nck appears to prefer ligands containing the APxxPxR motif. SH3 domains are protein interaction domains that usually bind to proline-rich ligands with moderate affinity and selectivity, preferentially a PxxP motif. 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 2008376973 597 YSYEAQGDDELSLKEGMTYELTpngESAGDGWWEGTDsSGRKGIFPSNYVER 648
Cdd:cd11766     6 FNYEAQREDELSLRKGDRVLVL---EKSSDGWWRGEC-NGQVGWFPSNYVTE 53

protein kinase C conserved region 1 (C1 domain) found in the myotubularin-related protein Sbf and similar proteins; This group includes Drosophila melanogaster SET domain binding factor (Sbf), the single homolog of human MTMR5/MTMR13, and similar proteins, that show high sequence similarity to vertebrate myotubularin-related proteins (MTMRs) which may function as guanine nucleotide exchange factors (GEFs). Sbf is a pseudophosphatase that coordinates both phosphatidylinositol 3-phosphate (PI(3)P) turnover and Rab21 GTPase activation in an endosomal pathway that controls macrophage remodeling. It also functions as a GEF that promotes Rab21 GTPase activation associated with PI(3)P endosomes. Vertebrate MTMR5 and MTMR13 contain an N-terminal DENN domain, a PH-GRAM domain, an inactive PTP domain, a SET interaction domain, a coiled-coil domain, and a C-terminal PH domain. Members of this family contain these domains and have an additional C1 domain. This model corresponds to the C1 domain. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.

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gi 2008376973 397 PHEFKSASFSIPSPCGYCKSNIWGLSKPGKTCRNCGISVHTRCELKMPAEC 447
Cdd:cd20827     1 PHRFEKHNFTTPTYCDYCSSLLWGLVKTGMRCADCGYSCHEKCLEHVPKNC 51

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 2008376973 593 VKALYSYEAQGDDELSLKEGMtyELTPNGESAGDGWWEGTDSSGRKGIFPSNYVE 647
Cdd:cd11998     3 VRALYDYDGQEQDELSFKAGD--ELTKLEDEDEQGWCKGRLDSGQVGLYPANYVE 55

Src Homology 3 domain of Sorting nexin 9; Sorting nexin 9 (SNX9), also known as SH3PX1, is a cytosolic protein that interacts with proteins associated with clathrin-coated pits such as Cdc-42-associated tyrosine kinase 2 (ACK2). It binds class I polyproline sequences found in dynamin 1/2 and the WASP/N-WASP actin regulators. SNX9 is localized to plasma membrane endocytic sites and acts primarily in clathrin-mediated endocytosis. Its array of interacting partners suggests that SNX9 functions at the interface between endocytosis and actin cytoskeletal organization. SNXs are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNX9 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.

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gi 2008376973 515 KAKVLYSYEAS-GEFEVSITEDTTVQVVEPDDGSGWVKVVNERGAEGLVPATYVEIV 570
Cdd:cd11898     1 KARVLYDFAAEpGNNELTVKEGEIITVTNPNVGGGWIEAKNSQGERGLVPTDYVEIV 57

Second Src Homology 3 domain of Bzz1 and similar domains; Bzz1 (or Bzz1p) is a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Together with other proteins, it induces membrane scission in yeast. Bzz1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. This model represents the second 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 2008376973 593 VKALYSYEAQGDDELSLKEGMTyeLTPNGESAGDGWWEGtDSSGRKGIFPSNY 645
Cdd:cd11778     2 VEALYDYEAQGDDEISIRVGDR--IAVIRGDDGSGWTYG-EINGVKGLFPTSY 51

Third Src Homology 3 domain (SH3C) of CD2-associated protein and similar proteins; This 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 2008376973 593 VKALYSYEAQGDDELSLKEGMTYELTpNGESAGDGWWEGtDSSGRKGIFPSNYVE 647
Cdd:cd11875     2 ARVLFDYEAENEDELTLREGDIVTIL-SKDCEDKGWWKG-ELNGKRGVFPDNFVE 54

Third Src Homology 3 domain of SH3 domain containing ring finger 1 (SH3RF1), SH3RF3, and similar domains; SH3RF1 (or POSH) and SH3RF3 (or POSH2) are scaffold proteins that function as E3 ubiquitin-protein ligases. They contain an N-terminal RING finger domain and four SH3 domains. This model represents the third SH3 domain, located in the middle of SH3RF1 and SH3RF3, and similar domains. SH3RF1 plays a role in calcium homeostasis through the control of the ubiquitin domain protein Herp. It may also have a role in regulating death receptor mediated and JNK mediated apoptosis. SH3RF3 interacts with p21-activated kinase 2 (PAK2) and GTP-loaded Rac1. It may play a role in regulating JNK mediated apoptosis in certain conditions. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 2008376973 595 ALYSYEAQGDDELSLKEGMTYELTpngESAGDGWWEGTD-SSGRKGIFPSNYV 646
Cdd:cd11783     4 ALYPYKPQKPDELELRKGEMYTVT---EKCQDGWFKGTSlRTGQSGVFPGNYV 53

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

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gi 2008376973 594 KALYSYEAQGDDELSLKEGMTYELTpngESAGDGWWEGT-DSSGRKGIFPSNYVER 648
Cdd:cd11780     3 RALYSYTPQNEDELELREGDIVYVM---EKCDDGWFVGTsERTGLFGTFPGNYVAR 55

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

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gi 2008376973 593 VKALYSYEAQGDDELSLKEGmtYELTPNGESAGDGWWEGTdSSGRKGIFPSNYVE 647
Cdd:cd11843     2 VRALYDYEGQESDELSFKAG--DILTKLEEEDEQGWCKGR-LDGRVGLYPANYVE 53

Src homology 3 domain of High osmolarity signaling protein Sho1p; Sho1p (or Sho1), also called SSU81 (Suppressor of SUA8-1 mutation), is a yeast membrane protein that regulates adaptation to high salt conditions by activating the HOG (high-osmolarity glycerol) pathway. High salt concentrations lead to the localization to the membrane of the MAPKK Pbs2, which is then activated by the MAPKK Ste11 and in turn, activates the MAPK Hog1. Pbs2 is localized to the membrane though the interaction of its PxxP motif with the SH3 domain of Sho1p. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity. 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 2008376973 593 VKALYSYEAQGDD--ELSLKEGMTYELTpngESAGDgWWEGTDSSGRKGIFPSNYVE 647
Cdd:cd11855     2 ARALYPYDASPDDpnELSFEKGEILEVS---DTSGK-WWQARKSNGETGICPSNYLQ 54

protein kinase C conserved region 1 (C1 domain) found in the chimaerin family; Chimaerins are a family of phorbolester- and diacylglycerol-responsive GTPase activating proteins (GAPs) specific for the Rho-like GTPase Rac. Alpha1-chimerin (formerly known as N-chimerin) and alpha2-chimerin are alternatively spliced products of a single gene, as are beta1- and beta2-chimerin. Alpha1- and beta1-chimerin have a relatively short N-terminal region that does not encode any recognizable domains, whereas alpha2- and beta2-chimerin both include a functional SH2 domain that can bind to phosphotyrosine motifs within receptors. All the isoforms contain a GAP domain with specificity in vitro for Rac1 and a diacylglycerol (DAG)-binding C1 domain which allows them to translocate to membranes in response to DAG signaling and anchors them in close proximity to activated Rac. This model corresponds to the C1 domain. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.

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gi 2008376973 397 PHEFKSASFSIPSPCGYCKSNIWGLSKPGKTCRNCGISVHTRCELKMPAEC 447
Cdd:cd20806     1 PHNFKVHTFKGPHWCDYCGNFMWGLIAQGVKCEDCGFNAHKQCSKLVPHDC 51

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 2008376973 593 VKALYSYEAQGDDELSLKEGmtyELTPNGESAGDGWWEGTdSSGRKGIFPSNYVE 647
Cdd:cd11873     2 VIVEFDYDAEEPDELTLKVG---DIITNVKKMEEGWWEGT-LNGKRGMFPDNFVK 52

protein kinase C conserved region 1 (C1 domain) found in the SH3 and cysteine-rich domain-containing protein (Stac) family; Stac proteins are putative adaptor proteins that are important for neuronal function. There are three mammalian members (Stac1, Stac2 and Stac3) of this family. Stac1 and Stac3 contain two SH3 domains while Stac2 contains a single SH3 domain at the C-terminus. Stac1 and Stac2 have been found to be expressed differently in mature dorsal root ganglia (DRG) neurons. Stac1 is mainly expressed in peptidergic neurons while Stac2 is found in a subset of nonpeptidergic and all trkB+ neurons. Stac proteins contain a cysteine-rich C1 domain and one or two SH3 domains at the C-terminus. This model corresponds to the C1 domain. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.

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gi 2008376973 398 HEFKSASFSIPSPCGYCKSNIWGLSKPGKTCRNCGISVHTRC 439
Cdd:cd20817     1 HSFQEHTFKKPTFCDVCKELLVGLSKQGLRCKNCKMNVHHKC 42

first protein kinase C conserved region 1 (C1 domain) found in novel protein kinase C (nPKC) theta, delta, and similar proteins; PKCs are classified into three groups (classical, atypical, and novel) depending on their mode of activation and the structural characteristics of their regulatory domains. nPKCs are calcium-independent, but require DAG (1,2-diacylglycerol) and phosphatidylserine (PS) for activity. PKC-theta is selectively expressed in T-cells and plays an important and non-redundant role in several aspects of T-cell biology. PKC-delta plays a role in cell cycle regulation and programmed cell death in many cell types. Members of this family contain two copies of the C1 domain. This model corresponds to the first one. The C1 domain is a cysteine-rich zinc binding domain that does not bind DNA nor possess structural similarity to conventional zinc finger domains; it contains two separate Zn(2+)-binding sites.

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gi 2008376973 396 KPHEFKSASFSIPSPCGYCKSNIWGLSKPGKTCRNCGISVHTRCELKMPAEC 447
Cdd:cd20834     6 KGHEFIAKFFRQPTFCSVCKEFLWGFNKQGYQCRQCNAAVHKKCHDKILGKC 57

Third Src Homology 3 domain of the fungal endocytic adaptor protein Sla1p; Sla1p facilitates endocytosis by playing a role as an adaptor protein in coupling components of the actin cytoskeleton to the endocytic machinery. It interacts with Abp1p, Las17p and Pan1p, which are activator proteins of actin-related protein 2/3 (Arp2/3). Sla1p contains multiple domains including three SH3 domains, a SAM (sterile alpha motif) domain, and a Sla1 homology domain 1 (SHD1), which binds to the NPFXD motif that is found in many integral membrane proteins such as the Golgi-localized Arf-binding protein Lsb5p and the P4-ATPases, Drs2p and Dnf1p. The third SH3 domain of Sla1p can bind ubiquitin while retaining the ability to bind proline-rich ligands; monoubiquitination of target proteins signals internalization and sorting through the endocytic pathway. 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 2008376973 591 KLVKALYSYEAQGDDELSLKEGMTYELTPNGESagDGWWE-GTDSSGRKGIFPSNYVER 648
Cdd:cd11775     1 KRGKVLYDFDAQSDDELTVKEGDVVYILDDKKS--KDWWMvENVSTGKEGVVPASYIEI 57