protein kinase C conserved region 1 (C1 domain) found in SH3 and cysteine-rich domain-containing protein 3 (Stac3) and similar proteins; Stac3 is an essential component of the skeletal muscle excitation-contraction coupling (ECC) machinery. It is required for normal excitation-contraction coupling in skeletal muscle and for normal muscle contraction in response to membrane depolarization. It plays an essential role for normal Ca2+ release from the sarcplasmic reticulum, which ultimately leads to muscle contraction. Stac3 contains a cysteine-rich C1 domain and 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 564359652  84 VNDKPHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYVEMQKCFGK 142
Cdd:cd20882    1 VNDKPHKFKDHYFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHHHCQSYVEFQRCFGK 59

Second C-terminal Src homology 3 domain of SH3 and cysteine-rich domain-containing proteins 1 and 3; This model represents the second C-terminal SH3 domain of Stac1 and Stac3. Stac proteins are putative adaptor proteins that contain a cysteine-rich C1 domain and one or two SH3 domains at the C-terminus. 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. 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 564359652 307 VHRVTRSFVGNREIGQITLKKDQIVVQKGDEAGGYVKVYTGRKVGLFPTDF 357
Cdd:cd11834    1 VHRVTRSFVGNKEIGQITLKKDQIVVQKGEEQNGYIKVYTGRKVGLFPLDF 51

protein kinase C conserved region 1 (C1 domain) found in SH3 and cysteine-rich domain-containing protein 3 (Stac3) and similar proteins; Stac3 is an essential component of the skeletal muscle excitation-contraction coupling (ECC) machinery. It is required for normal excitation-contraction coupling in skeletal muscle and for normal muscle contraction in response to membrane depolarization. It plays an essential role for normal Ca2+ release from the sarcplasmic reticulum, which ultimately leads to muscle contraction. Stac3 contains a cysteine-rich C1 domain and 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 564359652  84 VNDKPHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYVEMQKCFGK 142
Cdd:cd20882    1 VNDKPHKFKDHYFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHHHCQSYVEFQRCFGK 59

Second C-terminal Src homology 3 domain of SH3 and cysteine-rich domain-containing proteins 1 and 3; This model represents the second C-terminal SH3 domain of Stac1 and Stac3. Stac proteins are putative adaptor proteins that contain a cysteine-rich C1 domain and one or two SH3 domains at the C-terminus. 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. 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 564359652 307 VHRVTRSFVGNREIGQITLKKDQIVVQKGDEAGGYVKVYTGRKVGLFPTDF 357
Cdd:cd11834    1 VHRVTRSFVGNKEIGQITLKKDQIVVQKGEEQNGYIKVYTGRKVGLFPLDF 51

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 564359652  250 VALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGK-IGEKVGFFP 294
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVLEKSEDGWWKGRnKGGKEGLIP 46

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
                   ....*....|....*....|....*....|....*....|....
gi 564359652    89 HKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQS 132
Cdd:smart00109   1 HKHVFRTFTKPTFCCVCRKSIWGSFKQGLRCSECKVKCHKKCAD 44

Unstructured on SH3 and cysteine-rich domain-containing protein 2; STAC2_u1 is a region of natively unstructured but highly conserved sequence between C1_1 pfam00130, and an SH3 domain, eg pfam00018, on SH3 and cysteine-rich domain-containing proteins from higher eukaryotes. The function is not known.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 564359652  146 GFHRAYSSPLYSNQQYACV------SAANRNDPVFETLRVGVIMANKERKKGQADKKNPLAAMMEEEPESARPEEGKS 217
Cdd:pfam16664   2 AFRRNFSSPLLIEDQLGVVkevppaAGNKKVDPVYEALRYGTSLAQMSRSSFGSSSESPTRSLHESREELEDKQSSPS 79

protein kinase C conserved region 1 (C1 domain) found in SH3 and cysteine-rich domain-containing protein 3 (Stac3) and similar proteins; Stac3 is an essential component of the skeletal muscle excitation-contraction coupling (ECC) machinery. It is required for normal excitation-contraction coupling in skeletal muscle and for normal muscle contraction in response to membrane depolarization. It plays an essential role for normal Ca2+ release from the sarcplasmic reticulum, which ultimately leads to muscle contraction. Stac3 contains a cysteine-rich C1 domain and 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*....
gi 564359652  84 VNDKPHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYVEMQKCFGK 142
Cdd:cd20882    1 VNDKPHKFKDHYFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHHHCQSYVEFQRCFGK 59

First C-terminal Src homology 3 domain of SH3 and cysteine-rich domain-containing (Stac) proteins; Stac proteins are putative adaptor proteins that contain a cysteine-rich C1 domain and one or two SH3 domains at the C-terminus. 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. This model represents the first C-terminal SH3 domain of Stac1 and Stac3, and the single C-terminal SH3 domain of Stac2. 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. 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 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFIIR 300
Cdd:cd11833    1 TYVALYKFKPQENEDLEMRPGDKITLLDDSNEDWWKGKIEDRVGFFPANFVQR 53

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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 564359652  89 HKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYVEM 136
Cdd:cd20817    1 HSFQEHTFKKPTFCDVCKELLVGLSKQGLRCKNCKMNVHHKCQEGVPD 48

protein kinase C conserved region 1 (C1 domain) found in SH3 and cysteine-rich domain-containing protein (Stac1) and similar proteins; Stac1, also called Src homology 3 and cysteine-rich domain-containing protein, promotes expression of the ion channel CACNA1H at the cell membrane, and thereby contributes to the regulation of channel activity. It plays a minor and redundant role in promoting the expression of calcium channel CACNA1S at the cell membrane, and thereby contributes to increased channel activity. It slows down the inactivation rate of the calcium channel CACNA1C. Stac1 contains a cysteine-rich C1 domain and 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 564359652  87 KPHKFKDHFFKKPKFCDVCARMIV-LNNKFGLRCKNCKTNIHEHCQSYVEMQKCFGK 142
Cdd:cd20880    1 KAHSFQEYIFKKPTFCDVCNHMIVgTNAKHGLRCKACKMSIHHKCTDGIGQQRCMGK 57

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 564359652   245 QSHYFVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIG-EKVGFFPPNFI 298
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRLGrGKEGLFPSNYV 55

Src homology 3 domain of Ysc84p and similar fungal proteins; This family is composed of the Saccharomyces cerevisiae proteins, Ysc84p (also called LAS17-binding protein 4, Lsb4p) and Lsb3p, and similar fungal proteins. They contain an N-terminal SYLF domain (also called DUF500) and a C-terminal SH3 domain. Ysc84p localizes to actin patches and plays an important in actin polymerization during endocytosis. The N-terminal domain of both Ysc84p and Lsb3p can bind and bundle actin filaments. A study of the yeast SH3 domain interactome predicts that the SH3 domains of Lsb3p and Lsb4p may function as molecular hubs for the assembly of endocytic complexes. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVID--DSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11842    1 KAVALYDFAGEQPGDLAFQKGDIITILKksDSQNDWWTGRIGGREGIFPANYV 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
                 ....*....|....*....|....*....|....*....|....*.
gi 564359652  89 HKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYV 134
Cdd:cd00029    1 HRFVPTTFSSPTFCDVCGKLIWGLFKQGLKCSDCGLVCHKKCLDKA 46

Src homology 3 domain of Signal Transducing Adaptor Molecule 2; STAM2, also called EAST (Epidermal growth factor receptor-associated protein with SH3 and TAM domain) or Hbp (Hrs binding protein), is part of the endosomal sorting complex required for transport (ESCRT-0). It plays a role in sorting mono-ubiquinated endosomal cargo for trafficking to the lysosome for degradation. It is also involved in the regulation of exocytosis. 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. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 564359652 251 ALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11963    6 ALYDFEAVEDNELTFKHGEIIIVLDDSDANWWKGENHRGVGLFPSNFV 53

second protein kinase C conserved region 1 (C1 domain) found in novel protein kinase C (nPKC) epsilon, eta, 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. nPKCs are calcium-independent, but require DAG (1,2-diacylglycerol) and phosphatidylserine (PS) for activity. PKC-epsilon has been shown to behave as an oncoprotein. Its overexpression contributes to neoplastic transformation depending on the cell type. It contributes to oncogenesis by inducing disordered cell growth and inhibiting cell death. It also plays a role in tumor invasion and metastasis. PKC-epsilon has also been found to confer cardioprotection against ischemia and reperfusion-mediated damage. Other cellular functions include the regulation of gene expression, cell adhesion, and cell motility. PKC-eta is predominantly expressed in squamous epithelia, where it plays a crucial role in the signaling of cell-type specific differentiation. It is also expressed in pro-B cells and early-stage thymocytes, and acts as a key regulator in early B-cell development. PKC-eta increases glioblastoma multiforme (GBM) proliferation and resistance to radiation, and is being developed as a therapeutic target for the management of GBM. 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 564359652  88 PHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYV 134
Cdd:cd20838    2 PHRFSVHNYKRPTFCDHCGSLLYGLYKQGLQCKVCKMNVHKRCQKNV 48

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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 564359652 251 ALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11950    4 ALYDFEALEDDELGFNSGDVIEVLDSSNPSWWKGRLHGKLGLFPANYV 51

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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 564359652  89 HKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYV 134
Cdd:cd20793    1 HKFKVHTYYSPTFCDHCGSLLYGLVRQGLKCKDCGMNVHHRCKENV 46

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
                   ....*....|....*....|....*....|....*....|....
gi 564359652    89 HKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQS 132
Cdd:smart00109   1 HKHVFRTFTKPTFCCVCRKSIWGSFKQGLRCSECKVKCHKKCAD 44

Src homology 3 domain of SH3 domain containing Ysc84-like 1 (SH3YL1) protein; SH3YL1 localizes to the plasma membrane and is required for dorsal ruffle formation. It binds phosphoinositides (PIs) with high affinity through its N-terminal SYLF domain (also called DUF500). In addition, SH3YL1 contains a C-terminal SH3 domain which has been reported to bind to N-WASP, dynamin 2, and SHIP2 (a PI 5-phosphatase). SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 564359652 251 ALYRFKALEKDDLDFPPGEKITVID--DSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11841    4 ALYSFEGQQPCDLSFQAGDRITVLTrtDSQFDWWEGRLRGRVGIFPANYV 53

Src homology 3 domain of Cortactin; Cortactin was originally identified as a substrate of Src kinase. It is an actin regulatory protein that binds to the Arp2/3 complex and stabilizes branched actin filaments. It is involved in cellular processes that affect cell motility, adhesion, migration, endocytosis, and invasion. It is expressed ubiquitously except in hematopoietic cells, where the homolog hematopoietic lineage cell-specific 1 (HS1) is expressed instead. Cortactin 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 interacts with the Arp2/3 complex and F-actin, and is crucial in regulating branched actin assembly. Cortactin also serves as a scaffold and provides a bridge to the actin cytoskeleton for membrane trafficking and signaling proteins that bind to its SH3 domain. Binding partners for the SH3 domain of cortactin include dynamin2, N-WASp, MIM, FGD1, 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
                 ....*....|....*....|....*....|....*....|....*....
gi 564359652 250 VALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11959    3 VALYDYQAADDDEISFDPDDIITNIEMIDEGWWRGVCRGKYGLFPANYV 51

Third Src homology 3 domain (or SH3C) of Intersectin; Intersectins (ITSNs) are adaptor proteins that function in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. They are essential for initiating clathrin-coated pit formation. They bind to many proteins through their multidomain structure and facilitate the assembly of multimeric complexes. Vertebrates contain two ITSN proteins, ITSN1 and ITSN2, which exist in alternatively spliced short and long isoforms. The short isoforms contain two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoforms, in addition, contain RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. ITSN1 and ITSN2 are both widely expressed, with variations depending on tissue type and stage of development. The third SH3 domain (or SH3C) of ITSN1 has been shown to bind many proteins including dynamin1/2, CIN85, c-Cbl, SHIP2, Reps1, synaptojanin-1, and WNK, among others. The SH3C of ITSN2 has been shown to bind the K15 protein of Kaposi's sarcoma-associated herpesvirus. 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 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVIDDSNEeWWRGKIGEKVGFFPPNFI 298
Cdd:cd11838    1 EYIALYPYESNEPGDLTFNAGDVILVTKKDGE-WWTGTIGDRTGIFPSNYV 50

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
                 ....*....|....*....|....*....|....*....|....*....
gi 564359652 250 VALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd12073    4 VALYDYQGEGDDEISFDPQETITDIEMVDEGWWKGTCHGHRGLFPANYV 52

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 564359652 249 FVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFII 299
Cdd:cd11772    2 FRALYDYEAQHPDELSFEEGDLLYISDKSDPNWWKATCGGKTGLIPSNYVE 52

Third Src homology 3 domain (or SH3C) of Intersectin-1; Intersectin-1 (ITSN1) is an adaptor protein that functions in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. It plays a role in clathrin-coated pit (CCP) formation. It binds to many proteins through its multidomain structure and facilitate the assembly of multimeric complexes. ITSN1 localizes in membranous organelles, CCPs, the Golgi complex, and may be involved in the cell membrane trafficking system. It exists in alternatively spliced short and long isoforms. The short isoform contains two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoform, in addition, contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. The third SH3 domain (or SH3C) of ITSN1 has been shown to bind many proteins including dynamin1/2, CIN85, c-Cbl, SHIP2, Reps1, synaptojanin-1, and WNK, 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 564359652 249 FVALYRFKALEKDDLDFPPGEKITVIDDSNEeWWRGKIGEKVGFFPPNFI 298
Cdd:cd11991    2 YVAMYTYESNEQGDLTFQQGDVILVTKKDGD-WWTGTVGDKTGVFPSNYV 50

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 564359652 249 FVALYRFKALEKDDLDFPPGEKITVIDDSNEEWW--RGKIGEKVGFFPPNF 297
Cdd:cd11845    2 YVALYDYEARTDDDLSFKKGDRLQILDDSDGDWWlaRHLSTGKEGYIPSNY 52

second 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 domain. 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 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*.
gi 564359652  89 HKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYV 134
Cdd:cd20837    1 HRFKVYNYMSPTFCDHCGSLLWGLFRQGLKCEECGMNVHHKCQKKV 46

C-terminal (or second) Src Homology 3 domain of the p67phox subunit of NADPH oxidase; p67phox, also called Neutrophil cytosol factor 2 (NCF-2), is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) which plays a crucial role in the cellular response to bacterial infection. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p67phox plays a regulatory role and contains N-terminal TPR, first SH3 (or N-terminal or central SH3), PB1, and C-terminal SH3 domains. It binds, via its C-terminal SH3 domain, to a proline-rich region of p47phox and upon activation, this complex assembles with flavocytochrome b558, the Nox2-p22phox heterodimer. Concurrently, RacGTP translocates to the membrane and interacts with the TPR domain of p67phox, which leads to the activation of NADPH oxidase. The PB1 domain of p67phox binds to its partner PB1 domain in p40phox, and this facilitates the assembly of p47phox-p67phox at the membrane. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd12046    1 QVVALFSYEASQPEDLEFQKGDVILVLSKVNEDWLEGQCKGKIGIFPSAFV 51

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 564359652  87 KPHKFKDHFFKKPKFCDVCARMIvlnNKFGLRCKNCKTNIHEHCQSYVeMQKC 139
Cdd:cd20826    1 KSHSFKEKSFRKPRTCDVCKQII---WNEGSSCRVCKYACHRKCEPKV-TAAC 49

protein kinase C conserved region 1 (C1 domain) found in uncharacterized proteins similar to myotubularin-related proteins; The family includes a group of uncharacterized proteins that show high sequence similarity to vertebrate myotubularin-related proteins (MTMRs), such as MTMR5 and MTMR13. MTMRs may function as guanine nucleotide exchange factors (GEFs). 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 564359652  88 PHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYVEMQ 137
Cdd:cd20828    5 PHNFEPHSFVTPTNCDYCLQILWGIVKKGMKCSECGYNCHEKCQPQVPKQ 54

Src homology 3 domain of ARHGEF9-like Rho guanine nucleotide exchange factors; Members of this family contain a SH3 domain followed by RhoGEF (also called Dbl-homologous or DH) and Pleckstrin Homology (PH) domains. They include the Rho guanine nucleotide exchange factors ARHGEF9, ASEF (also called ARHGEF4), ASEF2, and similar proteins. GEFs activate small GTPases by exchanging bound GDP for free GTP. ARHGEF9 specifically activates Cdc42, while both ASEF and ASEF2 can activate Rac1 and Cdc42. ARHGEF9 is highly expressed in the brain and it interacts with gephyrin, a postsynaptic protein associated with GABA and glycine receptors. ASEF plays a role in angiogenesis and cell migration. ASEF2 is important in cell migration and adhesion dynamics. ASEF exists in an autoinhibited form and is activated upon binding of the tumor suppressor APC (adenomatous polyposis coli), leading to the activation of Rac1 or Cdc42. In its autoinhibited form, the SH3 domain of ASEF forms an extensive interface with the DH and PH domains, blocking the Rac binding site. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 564359652 251 ALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11828    4 ALWDHVTMDPEELGFKAGDVIEVLDMSDKDWWWGSIRDEEGWFPASFV 51

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 564359652 249 FVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11856    2 YVAIADYEAQGDDEISLQEGEVVEVLEKNDSGWWYVRKGDKEGWVPASYL 51

C-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 C-terminal SH3 domains (SH3c) of the related proteins, 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 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11951    1 FVQAQYDFSAEDPSQLSFRRGDIIEVLDCPDPNWWRGRISGRVGFFPRNYV 51

Src Homology 3 domain of Apoptosis Stimulating of p53 protein 1; ASPP1, like ASPP2, activates the apoptotic function of the p53 family of tumor suppressors (p53, p63, and p73). In addition, it functions in the cytoplasm to regulate the nuclear localization of the transcriptional cofactors YAP and TAZ by inihibiting their phosphorylation; YAP and TAZ are important regulators of cell expansion, differentiation, migration, and invasion. ASPP1 is downregulated in breast tumors expressing wild-type p53. 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 ASPP1 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 564359652 251 ALYRFKALEKDDLDFPPGEKITVI---DDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11954    5 ALWDYEAQNADELSFQEGDAITILrrkDDSETEWWWARLNDKEGYVPKNLL 55

first protein kinase C conserved region 1 (C1 domain) found in type I diacylglycerol kinases; Diacylglycerol (DAG) kinase (EC 2.7.1.107) is a lipid kinase that phosphorylates diacylglycerol to form phosphatidic acid. Type I DAG kinases (DGKs) contain EF-hand structures that bind Ca(2+) and recoverin homology domains, in addition to C1 and catalytic domains that are present in all DGKs. Type I DGKs, regulated by calcium binding, include three DGK isozymes (alpha, beta and gamma). DAG kinase alpha, also called 80 kDa DAG kinase, or diglyceride kinase alpha (DGK-alpha), is active upon cell stimulation, initiating the resynthesis of phosphatidylinositols and attenuating protein kinase C activity. DAG kinase beta, also called 90 kDa DAG kinase, or diglyceride kinase beta (DGK-beta), exhibits high phosphorylation activity for long-chain diacylglycerols. DAG kinase gamma, also called diglyceride kinase gamma (DGK-gamma), reverses the normal flow of glycerolipid biosynthesis by phosphorylating diacylglycerol back to phosphatidic acid. Members of this family contain two copies of the C1 domain. This model corresponds to the first one. DGK-alpha contains atypical C1 domains, while DGK-beta and DGK-gamma contain typical C1 domains that bind DAG and phorbol esters. 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 564359652  86 DKPHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHC 130
Cdd:cd20799    3 DGQHVWRLKHFNKPAYCNVCENMLVGLRKQGLCCTFCKYTVHERC 47

first protein kinase C conserved region 1 (C1 domain) found in Caenorhabditis elegans serine/threonine-protein kinase DKF-1 and similar proteins; DKF-1 converts transient diacylglycerol (DAG) signals into prolonged physiological effects, independently of PKC. It plays a role in the regulation of growth and neuromuscular control of movement. It is involved in immune response to Staphylococcus aureus bacterium by activating transcription factor hlh-30 downstream of phospholipase plc-1. Members of this group 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*
gi 564359652  86 DKPHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHC 130
Cdd:cd20797    1 TRPHVVEVEQYMTPTFCDYCGEMLTGLMKQGVKCKNCRCNFHKRC 45

Src homology 3 domain of Myosins Ie, If, and similar proteins; Myosins Ie (MyoIe) and If (MyoIf) are nonmuscle, unconventional, long tailed, class I myosins containing an N-terminal motor domain and a myosin tail with TH1, TH2, and SH3 domains. MyoIe interacts with the endocytic proteins, dynamin and synaptojanin-1, through its SH3 domain; it may play a role in clathrin-dependent endocytosis. In the kidney, MyoIe is critical for podocyte function and normal glomerular filtration. Mutations in MyoIe is associated with focal segmental glomerulosclerosis, a disease characterized by massive proteinuria and progression to end-stage kidney disease. MyoIf is predominantly expressed in the immune system; it plays a role in immune cell motility and innate immunity. Mutations in MyoIf may be associated with the loss of hearing. The MyoIf gene has also been found to be fused to the MLL (Mixed lineage leukemia) gene in infant acute myeloid leukemias (AML). SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 564359652 251 ALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11827    4 ALYAYDAQDTDELSFNEGDIIEILKEDPSGWWTGRLRGKEGLFPGNYV 51

protein kinase C conserved region 1 (C1 domain) found in Schizosaccharomyces pombe protein BZZ1 and similar proteins; BZZ1 is a syndapin-like F-BAR protein that plays a role in endocytosis and trafficking to the vacuole. It functions with type I myosins to restore polarity of the actin cytoskeleton after NaCl stress. BZZ1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. Schizosaccharomyces pombe BZZ1 also harbors a C1 domain, but Saccharomyces cerevisiae BZZ1 doesn't have any. 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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 564359652  88 PHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYVE 135
Cdd:cd20824    1 PHNFKPHSFSIPTKCDYCGEKIWGLSKKGLSCKDCGFNCHIKCELKVP 48

Third Src homology 3 domain of Tyrosine kinase substrate (Tks) proteins; 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. Vertebrates contain two Tks proteins, Tks4 (Tyr kinase substrate with four SH3 domains) and Tks5 (Tyr kinase substrate with five SH3 domains), which display partially overlapping but non-redundant functions. Both associate with the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. Tks5 interacts with N-WASP and Nck, while Tks4 is essential for the localization of MT1-MMP (membrane-type 1 matrix metalloproteinase) to invadopodia. Tks proteins contain an N-terminal Phox homology (PX) domain and four or five SH3 domains. This model characterizes the third SH3 domain of Tks proteins. 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 564359652 247 HYFVaLYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd12017    1 EYFT-IGEFQATIQDGISFQKGQKVEVIDKNPSGWWYVKIDGKEGWAPSSYI 51

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 564359652 250 VALYRFKALEKDDLDFPPGEKITVID-----DSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11876    3 TALFDYDARGEDELTLRRGQPVEVLSkdaavSGDEGWWTGKIGDKVGIFPSNYV 56

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 564359652 251 ALYRFKALEKDDLD---FPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNF 297
Cdd:cd11787    4 ALYDFEMKDEDEKDcltFKKGDVITVIRRVDENWAEGRLGDKIGIFPISF 53

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11974    2 YAEALWDHVTMDDQELAFKAGDVIRVLEASNKDWWWGRNEDREAWFPASFV 52

protein kinase C conserved region 1 (C1 domain) found in the 190 kDa guanine nucleotide exchange factor (p190RhoGEF)-like family; The p190RhoGEF-like protein family includes p190RhoGEF, Rho guanine nucleotide exchange factor 2 (ARHGEF2), A-kinase anchor protein 13 (AKAP-13) and similar proteins. p190RhoGEF is a brain-enriched, RhoA-specific guanine nucleotide exchange factor that regulates signaling pathways downstream of integrins and growth factor receptors. It is involved in axonal branching, synapse formation and dendritic morphogenesis, as well as in focal adhesion formation, cell motility and B-lymphocytes activation. ARHGEF2 acts as a guanine nucleotide exchange factor (GEF) that activates Rho-GTPases by promoting the exchange of GDP for GTP. It is thought to play a role in actin cytoskeleton reorganization in different tissues since its activation induces formation of actin stress fibers. AKAP-13 is a scaffold protein that plays an important role in assembling signaling complexes downstream of several types of G protein-coupled receptors. It activates RhoA in response to signaling via G protein-coupled receptors via its function as Rho guanine nucleotide exchange factor. It may also activate other Rho family members. AKAP-13 plays a role in cell growth, cell development and actin fiber formation. Members of this family share a common domain architecture containing C1, RhoGEF or Dbl-homologous (DH), and Pleckstrin Homology (PH) domains. Some members may contain additional domains such as the DUF5401 domain. This model describes 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.

                         10        20        30
                 ....*....|....*....|....*....|....*
gi 564359652 102 CDVCARmiVLNNKFGLRCKNCKTNIHEH-CQSYVE 135
Cdd:cd20815   17 CDVCSK--PLTNKPALQCENCSVNVHDSsCKDQLA 49

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 564359652 249 FVALYRFKALEKDDLDFPPGEKITVIDDSNEEWWRGKIGEKVGFFPPNFI 298
Cdd:cd11766    2 AVVKFNYEAQREDELSLRKGDRVLVLEKSSDGWWRGECNGQVGWFPSNYV 51

Src homology 3 domain of Blk Protein Tyrosine Kinase; Blk is a member of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) PTKs. It is expressed specifically in B-cells and is involved in pre-BCR (B-cell receptor) signaling. Src kinases 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). 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVIdDSNEEWWRGK--IGEKVGFFPPNFIIR 300
Cdd:cd12009    1 CVIAQYDFVPSNERDLQLKKGEKLQVL-KSDGEWWLAKslTTGKEGYIPSNYVAR 54

second protein kinase C conserved region 1 (C1 domain) found in protein kinase D3 (PKD3) and similar proteins; PKD3 is also called PRKD3, PRKCN, serine/threonine-protein kinase D3 (nPKC-D3), protein kinase C nu type (nPKC-nu), or protein kinase EPK2. It converts transient diacylglycerol (DAG) signals into prolonged physiological effects, downstream of PKC. It is involved in the regulation of the cell cycle by modulating microtubule nucleation and dynamics. PKD3 acts as a key mediator in several cancer development signaling pathways. PKD3 contains N-terminal tandem cysteine-rich zinc binding C1 (PKC conserved region 1), central PH (Pleckstrin Homology), and C-terminal catalytic kinase domains. This model corresponds to the second 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 564359652  88 PHKFKDHFFKKPKFCDVCARMIVLNNKFGLRCKNCKTNIHEHCQSYVEmQKCFGKI 143
Cdd:cd20844    5 PHTFAVHSYTRPTICQYCKRLLKGLFRQGMQCKDCRFNCHKRCASKVP-RDCLGEV 59

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*...
gi 564359652 248 YFVALYRFKALEKDDLDFPPGEKITVID-DS----NEEWWRGKIGEKVGFFPPNFIIR 300
Cdd:cd12059    1 VWTAVFDYEASAEDELTLRRGDRVEVLSkDSavsgDEGWWTGKINDRVGIFPSNYVTS 58