C-terminal Src Homology 3 domain of Nebulette and LIM-nebulette (or Lasp2); Nebulette is a cardiac-specific protein that localizes to the Z-disc. It interacts with tropomyosin and is important in stabilizing actin thin filaments in cardiac muscles. Polymorphisms in the nebulette gene are associated with dilated cardiomyopathy, with some mutations resulting in severe heart failure. Nebulette is a 107kD protein that contains an N-terminal acidic region, multiple nebulin repeats, and a C-terminal SH3 domain. LIM-nebulette, also called Lasp2 (LIM and SH3 domain protein 2), is an alternatively spliced variant of nebulette. Although it shares a gene with nebulette, Lasp2 is not transcribed from a muscle-specific promoter, giving rise to its multiple tissue expression pattern with highest amounts in the brain. It can crosslink actin filaments and it affects cell spreading. Lasp2 is a 34kD protein containing an N-terminal LIM domain, three nebulin repeats, 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 530391935 876 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYIEFVN 933
Cdd:cd11935    1 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDEGWMYGTVQRTGRTGMLPANYIEFVN 58

The Nebulin repeat is present also in Las1; Tandem arrays of these repeats are known to bind actin.

                           10        20        30
                   ....*....|....*....|....*....|
gi 530391935   603 TAVKDSPEIERVKKNQQNISSVKYKEEIKH 632
Cdd:smart00227   2 TSVPDTPEILLAKKNQKLISDVKYKEDYEK 31

The Nebulin repeat is present also in Las1; Tandem arrays of these repeats are known to bind actin.

                           10        20
                   ....*....|....*....|....*.
gi 530391935   466 TDTLEMQHAKKAAEIASEKDYKRDLE 491
Cdd:smart00227   5 PDTPEILLAKKNQKLISDVKYKEDYE 30

Nebulin repeat;

                          10        20
                  ....*....|....*....|....*..
gi 530391935  732 TPEMERVKKNQENISSVKYTQDHKQMK 758
Cdd:pfam00880   2 TPEIVHAKKNAKLQSDVKYKEDYEKEK 28

C-terminal Src Homology 3 domain of Nebulette and LIM-nebulette (or Lasp2); Nebulette is a cardiac-specific protein that localizes to the Z-disc. It interacts with tropomyosin and is important in stabilizing actin thin filaments in cardiac muscles. Polymorphisms in the nebulette gene are associated with dilated cardiomyopathy, with some mutations resulting in severe heart failure. Nebulette is a 107kD protein that contains an N-terminal acidic region, multiple nebulin repeats, and a C-terminal SH3 domain. LIM-nebulette, also called Lasp2 (LIM and SH3 domain protein 2), is an alternatively spliced variant of nebulette. Although it shares a gene with nebulette, Lasp2 is not transcribed from a muscle-specific promoter, giving rise to its multiple tissue expression pattern with highest amounts in the brain. It can crosslink actin filaments and it affects cell spreading. Lasp2 is a 34kD protein containing an N-terminal LIM domain, three nebulin repeats, 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 530391935 876 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYIEFVN 933
Cdd:cd11935    1 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDEGWMYGTVQRTGRTGMLPANYIEFVN 58

Variant SH3 domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 530391935  880 AMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGtvQRTGRTGMLPANYIE 930
Cdd:pfam14604   1 ALYPYEPKDDDELSLQRGDVITVIEESEDGWWEG--INTGRTGLVPANYVE 49

The Nebulin repeat is present also in Las1; Tandem arrays of these repeats are known to bind actin.

                           10        20        30
                   ....*....|....*....|....*....|
gi 530391935   603 TAVKDSPEIERVKKNQQNISSVKYKEEIKH 632
Cdd:smart00227   2 TSVPDTPEILLAKKNQKLISDVKYKEDYEK 31

Nebulin repeat;

                          10        20
                  ....*....|....*....|....*...
gi 530391935  766 DTPAMRHVKEAQNHISMVKYHEDFEKTK 793
Cdd:pfam00880   1 DTPEIVHAKKNAKLQSDVKYKEDYEKEK 28

MAEBL; Provisional

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530391935  294 KASKMLSGREYKKLFEENKGMYHFDADAVEHLHHKGNAVLQSQVKYKEEYEKNKGKPMLEFVETPSYQASKEAQKMQSEK 373
Cdd:PTZ00121 1310 KAEEAKKADEAKKKAEEAKKKADAAKKKAEEAKKAAEAAKAEAEAAADEAEAAEEKAEAAEKKKEEAKKKADAAKKKAEE 1389

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530391935  374 VYKEDfekEIKGRSSLDLDKTPEFLHV----KYITNLLREKEYKKDLEN-----EIKGKGMELNSEVLDIQRAKRASEMA 444
Cdd:PTZ00121 1390 KKKAD---EAKKKAEEDKKKADELKKAaaakKKADEAKKKAEEKKKADEakkkaEEAKKADEAKKKAEEAKKAEEAKKKA 1466

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530391935  445 SEK----EYKKDLESIIKGKGMQ--AGTDTLEMQHAKKAAEIASEKDYKRDLETEIKGKGMQVSTDTLDVQRAKKASEMA 518
Cdd:PTZ00121 1467 EEAkkadEAKKKAEEAKKADEAKkkAEEAKKKADEAKKAAEAKKKADEAKKAEEAKKADEAKKAEEAKKADEAKKAEEKK 1546

                         250       260       270       280       290       300       310       320
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530391935  519 SQKQYKKDLE---NEIKGKGMQVSMDIPDILRAKRTSEIYSQRKYKDEAEKMLSNYSTIADTPEIQRiKTTQQNISAVFY 595
Cdd:PTZ00121 1547 KADELKKAEElkkAEEKKKAEEAKKAEEDKNMALRKAEEAKKAEEARIEEVMKLYEEEKKMKAEEAK-KAEEAKIKAEEL 1625

                         330       340       350       360       370       380       390       400
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530391935  596 KK--EVGAGTAVKDSPEIERVKKNQQ-----NISSVKYKEEIKHATA-ISDPPELKRVKENQKNISNLQYKEQNYKATPV 667
Cdd:PTZ00121 1626 KKaeEEKKKVEQLKKKEAEEKKKAEElkkaeEENKIKAAEEAKKAEEdKKKAEEAKKAEEDEKKAAEALKKEAEEAKKAE 1705

                         410       420       430       440
                  ....*....|....*....|....*....|....*....|....*
gi 530391935  668 SMTPEIERVRRNQEQLSavkyKGELQRGTAISdppELKRAKENQK 712
Cdd:PTZ00121 1706 ELKKKEAEEKKKAEELK----KAEEENKIKAE---EAKKEAEEDK 1743

The Nebulin repeat is present also in Las1; Tandem arrays of these repeats are known to bind actin.

                           10        20        30
                   ....*....|....*....|....*....|.
gi 530391935   315 YHFDADAVEHLHHKGNAVLQSQVKYKEEYEK 345
Cdd:smart00227   1 YTSVPDTPEILLAKKNQKLISDVKYKEDYEK 31

Nebulin repeat;

                          10        20
                  ....*....|....*....|....*..
gi 530391935  356 ETPSYQASKEAQKMQSEKVYKEDFEKE 382
Cdd:pfam00880   1 DTPEIVHAKKNAKLQSDVKYKEDYEKE 27

The Nebulin repeat is present also in Las1; Tandem arrays of these repeats are known to bind actin.

                           10        20        30
                   ....*....|....*....|....*....|.
gi 530391935   499 MQVSTDTLDVQRAKKASEMASQKQYKKDLEN 529
Cdd:smart00227   1 YTSVPDTPEILLAKKNQKLISDVKYKEDYEK 31

C-terminal Src Homology 3 domain of Nebulette and LIM-nebulette (or Lasp2); Nebulette is a cardiac-specific protein that localizes to the Z-disc. It interacts with tropomyosin and is important in stabilizing actin thin filaments in cardiac muscles. Polymorphisms in the nebulette gene are associated with dilated cardiomyopathy, with some mutations resulting in severe heart failure. Nebulette is a 107kD protein that contains an N-terminal acidic region, multiple nebulin repeats, and a C-terminal SH3 domain. LIM-nebulette, also called Lasp2 (LIM and SH3 domain protein 2), is an alternatively spliced variant of nebulette. Although it shares a gene with nebulette, Lasp2 is not transcribed from a muscle-specific promoter, giving rise to its multiple tissue expression pattern with highest amounts in the brain. It can crosslink actin filaments and it affects cell spreading. Lasp2 is a 34kD protein containing an N-terminal LIM domain, three nebulin repeats, 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 530391935 876 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYIEFVN 933
Cdd:cd11935    1 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDEGWMYGTVQRTGRTGMLPANYIEFVN 58

C-terminal Src Homology 3 domain of Nebulin; Nebulin is a giant filamentous protein (600-900 kD) that is expressed abundantly in skeletal muscle. It binds to actin thin filaments and regulates its assembly and function. Nebulin was thought to be part of a molecular ruler complex that is critical in determining the lengths of actin thin filaments in skeletal muscle since its length, which varies due to alternative splicing, correlates with the length of thin filaments in various muscle types. Recent studies indicate that nebulin regulates thin filament length by stabilizing the filaments and preventing depolymerization. Mutations in nebulin can cause nemaline myopathy, characterized by muscle weakness which can be severe and can lead to neonatal lethality. Nebulin contains an N-terminal LIM domain, many nebulin repeats/super repeats, 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 530391935 876 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYIE 930
Cdd:cd11933    2 KSFRAMYDYRAADDDEVSFKDGDTIVNVQTIDEGWMYGTVQRTGKTGMLPANYVE 56

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 530391935   876 RTYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRtGRTGMLPANYIE 930
Cdd:smart00326   3 PQVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRLGR-GKEGLFPSNYVE 56

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQrTGRTGMLPANYIE 930
Cdd:cd11960    3 RALYDYQAADDTEISFDPGDIITDIEQIDEGWWRGTGP-DGTYGLFPANYVE 53

Src Homology 3 domain superfamily; Src Homology 3 (SH3) domains are protein interaction domains that bind proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. Thus, they are referred to as proline-recognition domains (PRDs). SH3 domains are less selective and show more diverse specificity compared to other PRDs. They have been shown to bind peptide sequences that lack the PxxP motif; examples include the PxxDY motif of Eps8 and the RKxxYxxY sequence in SKAP55. SH3 domain containing proteins play versatile and diverse roles in the cell, including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies, among others. Many members of this superfamily are adaptor proteins that associate with a number of protein partners, facilitating complex formation and signal transduction.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 530391935 877 TYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRtGRTGMLPANY 928
Cdd:cd00174    1 YARALYDYEAQDDDELSFKKGDIITVLEKDDDGWWEGELNG-GREGLFPANY 51

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPID-DGWMYGTVQrtGRTGMLPANYIEF 931
Cdd:cd11882    3 RALYACKAEDESELSFEPGQIITNVQPSDePGWLEGTLN--GRTGLIPENYVEF 54

Third (or C-terminal) Src Homology 3 domain of Sorbin and SH3 domain containing 1 (Sorbs1), also called ponsin; Sorbs1 is also called ponsin, SH3P12, or CAP (c-Cbl associated protein). It is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. It binds Cbl and plays a major role in regulating the insulin signaling pathway by enhancing insulin-induced phosphorylation of Cbl. Sorbs1, like vinexin, localizes at cell-ECM and cell-cell adhesion sites where it binds vinculin, paxillin, and afadin. It may function in the control of cell motility. Other interaction partners of Sorbs1 include c-Abl, Sos, flotillin, Grb4, ataxin-7, filamin C, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 530391935 877 TYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYIEFV 932
Cdd:cd11916    3 SYQALYSYAPQNDDELELRDGDIVDVMEKCDDGWFVGTSRRTKQFGTFPGNYVKLL 58

Third (or C-terminal) Src Homology 3 domain of Vinexin, also called Sorbin and SH3 domain containing 3 (Sorbs3); Vinexin is also called Sorbs3, SH3P3, and SH3-containing adapter molecule 1 (SCAM-1). It is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. Vinexin was first identified as a vinculin binding protein; it is co-localized with vinculin at cell-ECM and cell-cell adhesion sites. There are several splice variants of vinexin: alpha, which contains the SoHo and three SH3 domains and displays tissue-specific expression; and beta, which contains only the three SH3 domains and is widely expressed. Vinexin alpha stimulates the accumulation of F-actin at focal contact sites. Vinexin also promotes keratinocyte migration and wound healing. The SH3 domains of vinexin have been reported to bind a number of ligands including vinculin, WAVE2, DLG5, Abl, and Cbl. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 530391935 878 YRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYI 929
Cdd:cd11918    4 YKAVYQYRPQNEDELELREGDRVDVMQQCDDGWFVGVSRRTQKFGTFPGNYV 55

Src homology 3 domain of Endophilin-A; Endophilins play roles in synaptic vesicle formation, virus budding, mitochondrial morphology maintenance, receptor-mediated endocytosis inhibition, and endosomal sorting. They are classified into two types, A and B. Vertebrates contain three endophilin-A isoforms (A1, A2, and A3). Endophilin-A proteins are enriched in the brain and play multiple roles in receptor-mediated endocytosis. They tubulate membranes and regulate calcium influx into neurons to trigger the activation of the endocytic machinery. They are also involved in the sorting of plasma membrane proteins, actin filament assembly, and the uncoating of clathrin-coated vesicles for fusion with endosomes. Endophilins contain an N-terminal N-BAR domain (BAR domain with an additional N-terminal amphipathic helix), followed by a variable region containing proline clusters, 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 530391935 878 YRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQrtGRTGMLPANYIEFV 932
Cdd:cd11803    3 CRALYDFEPENEGELGFKEGDIITLTNQIDENWYEGMVN--GQSGFFPVNYVEVL 55

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQrtGRTGMLPANYIE 930
Cdd:cd11826    3 VALYDYTADKDDELSFQEGDIIYVTKKNDDGWYEGVLN--GVTGLFPGNYVE 52

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPIDD-GWMYGtvQRTGRTGMLPANYIE 930
Cdd:cd11843    3 RALYDYEGQESDELSFKAGDILTKLEEEDEqGWCKG--RLDGRVGLYPANYVE 53

Src homology 3 domain of an unknown subfamily of proteins with similarity to 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPIDD-GWMYGtVQRTGRTGMLPANYIE 930
Cdd:cd11999    5 RAVYDYTGQEPDELSFKAGEELLKVEDEDEqGWCKG-VTDGGAVGLYPANYVE 56

Src homology 3 domain of Proline-Serine-Threonine Phosphatase-Interacting Protein 1; PSTPIP1, also called CD2 Binding Protein 1 (CD2BP1), is mainly expressed in hematopoietic cells. It is a binding partner of the cell surface receptor CD2 and PTP-PEST, a tyrosine phosphatase which functions in cell motility and Rac1 regulation. It also plays a role in the activation of the Wiskott-Aldrich syndrome protein (WASP), which couples actin rearrangement and T cell activation. Mutations in the gene encoding PSTPIP1 cause the autoinflammatory disorder known as PAPA (pyogenic sterile arthritis, pyoderma gangrenosum, and acne) syndrome. PSTPIP1 contains an N-terminal F-BAR domain, PEST motifs, 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 530391935 878 YRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMygTVQRTGRTGMLPANYIE 930
Cdd:cd11824    2 YSVLYDYTAQEDDELSISKGDVVAVIEKGEDGWW--TVERNGQKGLVPGTYLE 52

Src homology 3 domain of Ubiquitin-associated and SH3 domain-containing protein B; UBASH3B, also called Suppressor of T cell receptor Signaling (STS)-1 or T cell Ubiquitin LigAnd (TULA)-2 is an active phosphatase that is expressed ubiquitously. The phosphatase activity of UBASH3B is essential for its roles in the suppression of TCR signaling and the regulation of EGFR. It also interacts with Syk and functions as a negative regulator of platelet glycoprotein VI signaling. TULA proteins contain an N-terminal UBA domain, a central SH3 domain, and a C-terminal histidine phosphatase domain. They bind c-Cbl through the SH3 domain and to ubiquitin via UBA. 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 530391935 877 TYRAMYDYSAQDEDEVSFRDGDYI----VNVQPIDDGWMYGTVQRTGRTGMLPANYI 929
Cdd:cd11936    3 TLQVIYPYTPQNDDELELVPGDYIfmspMEQTSTSEGWIYGTSLTTGCSGLLPENYI 59

Third (or C-terminal) Src Homology 3 domain of Sorbin and SH3 domain containing 2 (Sorbs2), also called Arg-binding protein 2 (ArgBP2); Sorbs2 or ArgBP2 is an adaptor protein containing one sorbin homology (SoHo) and three SH3 domains. It regulates actin-dependent processes including cell adhesion, morphology, and migration. It is expressed in many tissues and is abundant in the heart. Like vinexin, it is found in focal adhesion where it interacts with vinculin and afadin. It also localizes in epithelial cell stress fibers and in cardiac muscle cell Z-discs. Sorbs2 has been implicated to play roles in the signaling of c-Arg, Akt, and Pyk2. Other interaction partners of Sorbs2 include c-Abl, flotillin, spectrin, dynamin 1/2, synaptojanin, PTP-PEST, among others. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 530391935 878 YRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYIE 930
Cdd:cd11917    7 FQALYNYMPRNEDELELREGDVIDVMEKCDDGWFVGTSRRTKFFGTFPGNYVK 59

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.

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gi 530391935 878 YRAMYDYSAQDEDEVSFRDGDYI-VNVQPIDDGWMYGTVQRtGRTGMLPANYIE 930
Cdd:cd11763    2 VRALYDFDSQPSGELSLRAGEVLtITRQDVGDGWLEGRNSR-GEVGLFPSSYVE 54

Src Homology 3 domain of Amphiphysin and related domains; Amphiphysins function primarily in endocytosis and other membrane remodeling events. They exist in several isoforms and mammals possess two amphiphysin proteins from distinct genes. Amphiphysin I proteins, enriched in the brain and nervous system, contain domains that bind clathrin, Adaptor Protein complex 2 (AP2), dynamin, and synaptojanin. They function in synaptic vesicle endocytosis. Human autoantibodies to amphiphysin I hinder GABAergic signaling and contribute to the pathogenesis of paraneoplastic stiff-person syndrome. Some amphiphysin II isoforms, also called Bridging integrator 1 (Bin1), are localized in many different tissues and may function in intracellular vesicle trafficking. In skeletal muscle, Bin1 plays a role in the organization and maintenance of the T-tubule network. Mutations in Bin1 are associated with autosomal recessive centronuclear myopathy. Amphiphysins contain an N-terminal BAR domain with an additional N-terminal amphipathic helix (an N-BAR), a variable central domain, and a C-terminal SH3 domain. The SH3 domain of amphiphysins bind proline-rich motifs present in binding partners such as dynamin, synaptojanin, and nsP3. It also belongs to a subset of SH3 domains that bind ubiquitin in a site that overlaps with the peptide 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.

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gi 530391935 875 LRTYRAMYDYSAQDEDEVSFRDGDyIVNVQPIDD------GWMYGTVQRTGRTGMLPANYIE 930
Cdd:cd11790    2 LYKVRATHDYTAEDTDELTFEKGD-VILVIPFDDpeeqdeGWLMGVKESTGCRGVFPENFTE 62

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 530391935  879 RAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVqRTGRTGMLPA 926
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVLEKSEDGWWKGRN-KGGKEGLIPS 47

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

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gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQrtGRTGMLPANYIE 930
Cdd:cd11805    3 QALYDFNPQEPGELEFRRGDIITVLDSSDPDWWKGELR--GRVGIFPANYVQ 52

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 530391935 877 TYRAMYDYSAQDEDEVSFRDGD--YIVNVQPIDDGWMYGTVQrtGRTGMLPANYIE 930
Cdd:cd11875    1 KARVLFDYEAENEDELTLREGDivTILSKDCEDKGWWKGELN--GKRGVFPDNFVE 54

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 530391935 877 TYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQrtGRTGMLPANYIE 930
Cdd:cd11766    1 PAVVKFNYEAQREDELSLRKGDRVLVLEKSSDGWWRGECN--GQVGWFPSNYVT 52

C-terminal Src homology 3 domain of Growth factor receptor-bound protein 2; GRB2 is a critical signaling molecule that regulates the Ras pathway by linking tyrosine kinases to the Ras guanine nucleotide releasing protein Sos (son of sevenless), which converts Ras to the active GTP-bound state. It is ubiquitously expressed in all tissues throughout development and is important in cell cycle progression, motility, morphogenesis, and angiogenesis. In lymphocytes, GRB2 is associated with antigen receptor signaling components. GRB2 contains an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. The C-terminal SH3 domain of GRB2 binds to Gab2 (Grb2-associated binder 2) through epitopes containing RxxK motifs, as well as to the proline-rich C-terminus of FGRF2. SH3 domains are protein interaction domains that typically bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 530391935 877 TYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQrtGRTGMLPANYIE 930
Cdd:cd11949    1 YVQALFDFDPQEDGELGFRRGDFIEVMDNSDPNWWKGACH--GQTGMFPRNYVT 52

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

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gi 530391935 877 TYRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYgtVQRTGRTGMLPANYIE 930
Cdd:cd11856    1 SYVAIADYEAQGDDEISLQEGEVVEVLEKNDSGWWY--VRKGDKEGWVPASYLE 52

Third Src Homology 3 domain of SH3 domain containing ring finger 1, an E3 ubiquitin-protein ligase; SH3RF1 is also called POSH (Plenty of SH3s) or SH3MD2 (SH3 multiple domains protein 2). It is a scaffold protein that acts as an E3 ubiquitin-protein ligase. It plays a role in calcium homeostasis through the control of the ubiquitin domain protein Herp. It may also have a role in regulating death receptor mediated and JNK mediated apoptosis. SH3RF1 also enhances the ubiquitination of ROMK1 potassium channel resulting in its increased endocytosis. It contains an N-terminal RING finger domain and four SH3 domains. This model represents the third SH3 domain, located in the middle, 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.

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gi 530391935 878 YRAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYI 929
Cdd:cd11926    2 YVAIYPYTPRKEDELELRKGEMFLVFERCQDGWFKGTSMHTSKIGVFPGNYV 53

Src Homology 3 domain of eumetazoan Peroxisomal biogenesis factor 13; PEX13 is a peroxin and is required for protein import into the peroxisomal matrix and membrane. It is an integral membrane protein that is essential for the localization of PEX14 and the import of proteins containing the peroxisome matrix targeting signals, PTS1 and PTS2. Mutations of the PEX13 gene in humans lead to a wide range of peroxisome biogenesis disorders (PBDs), the most severe of which is known as Zellweger syndrome (ZS), a severe multisystem disorder characterized by hypotonia, psychomotor retardation, and neuronal migration defects. PEX13 contains two transmembrane regions 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 530391935 879 RAMYDYSAQDEDEVSFRDGDyIVNV-----QPIDDGWMYGTVQRTgRTGMLPANYIE 930
Cdd:cd11864    3 RAEYDFVAESEDELSFRAGD-KLRLapkelQPRVRGWLLATVDGQ-KIGLVPANYVK 57

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 530391935 878 YRAMYDYSAQDEDEVSFRDGD-YIVnVQPIDDGWMYGTVQRTGRTGMLPANYI 929
Cdd:cd11783    2 YVALYPYKPQKPDELELRKGEmYTV-TEKCQDGWFKGTSLRTGQSGVFPGNYV 53

Src Homology 3 domain of GTPase Regulator Associated with Focal adhesion kinase 3; GRAF3 is also called Rho GTPase activating protein 42 (ARHGAP42) or ARHGAP10-like. Though its function has not been characterized, it may be a GAP with activity towards RhoA and Cdc42, based on its similarity to GRAF and GRAF2. It contains an N-terminal BAR domain, followed by a Pleckstrin homology (PH) domain, a Rho GAP domain, and a C-terminal SH3 domain. The SH3 domain of GRAF and GRAF2 binds PKNbeta, a target of the small GTPase Rho. SH3 domains bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs; they play a role in the regulation of enzymes by intramolecular interactions, changing the subcellular localization of signal pathway components and mediate multiprotein complex assemblies.

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gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQP-IDDGWMYGTVQrtGRTGMLPANYIEFV 932
Cdd:cd12066    3 KAMYSCKAEHSHELSFPQGAIFSNVYPsVEPGWLKATYE--GKTGLVPENYVVFL 55

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.

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gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPiDD--GWmygTVQR--TGRTGMLPANYIEF 931
Cdd:cd11912    3 KVLYDYTASGDDEVSISEGEEVTVLEP-DDgsGW---TKVRngSGEEGLVPTSYIEI 55

Src Homology 3 domain of Ras GTPase-Activating Protein 1; RasGAP, also called Ras p21 protein activator, RASA1, or p120RasGAP, is part of the GAP1 family of GTPase-activating proteins. It is a 120kD cytosolic protein containing an SH3 domain flanked by two SH2 domains at the N-terminal end, a pleckstrin homology (PH) domain, a calcium dependent phospholipid binding domain (CaLB/C2), and a C-terminal catalytic GAP domain. It stimulates the GTPase activity of normal RAS p21. It acts as a positive effector of Ras in tumor cells. It also functions as a regulator downstream of tyrosine receptors such as those of PDGF, EGF, ephrin, and insulin, among others. The SH3 domain of RasGAP is unable to bind proline-rich sequences but have been shown to interact with protein partners such as the G3BP protein, Aurora kinases, and the Calpain small subunit 1. The RasGAP SH3 domain is necessary for the downstream signaling of Ras and it also influences Rho-mediated cytoskeletal reorganization. SH3 domains are protein interaction domains that typically bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 530391935 876 RTYRAMYDYSA-QDEDEVSFRDGDYIVNVQPIDDGWMYGTVQRTGRTGMLPANYIEFV 932
Cdd:cd11788    2 RRVRAILPYNKvPDTDELSFQKGDIFVVHNELEDGWLWVTSLRTGESGLVFRDLVEEL 59

First Src Homology 3 domain (SH3A) of Cbl-interacting protein of 85 kDa; CIN85, also called SH3 domain-containing kinase-binding protein 1 (SH3KBP1) or CD2-binding protein 3 (CD2BP3) or Ruk, is an adaptor protein that is involved in the downregulation of receptor tyrosine kinases by facilitating endocytosis through interaction with endophilin-associated ubiquitin ligase Cbl proteins. It is also important in many other cellular processes including vesicle-mediated transport, cytoskeletal remodelling, apoptosis, cell adhesion and migration, and viral infection, among others. CIN85 exists as multiple variants from alternative splicing; the main variant contains three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. This alignment model represents the first SH3 domain (SH3A) of 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. SH3A has also been shown to bind ubiquitin and to an atypical PXXXPR motif at the C-terminus of Cbl and the cytoplasmic end of the cell adhesion protein CD2. 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 530391935 882 YDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGTVQrtGRTGMLPANYI 929
Cdd:cd12052    6 FDYKAQHEDELTITVGDIITKIKKDDGGWWEGEIK--GRRGLFPDNFV 51

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

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gi 530391935 879 RAMYDYSAQDEDEVSFRDGDYIVNVQPIDDGWMYGtvQRTGRTGMLPANYIE 930
Cdd:cd11781    3 RALYPFKAQSAKELSLKKGDIIYIRRQIDKNWYEG--EHNGRVGIFPASYVE 52