Ephexin Pleckstrin homology (PH) domain; Ephexin-1 (also called NGEF/ neuronal guanine nucleotide exchange factor) plays a role in the homeostatic modulation of presynaptic neurotransmitter release. Specific functions are still unknown for Ephexin-2 (also called RhoGEF19) and Ephexin-3 (also called Rho guanine nucleotide exchange factor 5/RhoGEF5, Transforming immortalized mammary oncogene/p60 TIM, and NGEF/neuronalGEF). Ephexin-4 (also called RhoGEF16) acts downstream of EphA2 to promote ligand-independent breast cancer cell migration and invasion toward epidermal growth factor through activation of RhoG. This in turn results in the activation of RhoG which recruits ELMO2 and Dock4 to form a complex with EphA2 at the tips of cortactin-rich protrusions in migrating breast cancer cells. Ephexin-5 is the specific GEF for RhoA activation and the regulation of vascular smooth muscle contractility. It interacts with EPHA4 PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. The members of the Ephexin family contains a RhoGEF (DH) followed by a PH domain and an SH3 domain. The ephexin PH domain is believed to act with the DH domain in mediating protein-protein interactions. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959 387 KIKSVPIISHSRWLLKQGELQQMSGPKTSRTLRTKKLFREIYLFLFNDLLVICRQIPGDKYQVFDSAPRGLLRVEELEDQ 466
Cdd:cd01221    1 KIKAFPLISSSRWLVKRGELTELVEDGGSLTFRKKFSKTPVYLFLFNDLLLITKKKSEERYLVLDYAPRNLVQVEEVEDP 80

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 162417959 467 GQTL----ANVFILRLLENADDREATYMLKASSQSEMKRWMTSLAPNRRTK 513
Cdd:cd01221   81 LQLPqplgKNLFLLTLLENHEGKTVELLLSAESESDRERWLSALSPPKSEL 131

Src homology 3 domain of the Rho guanine nucleotide exchange factor, ephexin-1 (also called NGEF or ARHGEF27); Ephexin-1, also called NGEF (neuronal GEF) or ARHGEF27, activates RhoA, Tac1, and Cdc42 by exchanging bound GDP for free GTP. It is expressed mainly in the brain in a region associated with movement control. It regulates the stability of postsynaptic acetylcholine receptor (AChR) clusters and thus, plays a critical role in the maturation and neurotransmission of neuromuscular junctions. Ephexin-1 directly interacts with the ephrin receptor EphA4 and their coexpression enhances the ability of ephexin-1 to activate RhoA. It is required for normal axon growth and EphA-induced growth cone collapse. Ephexin-1 contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), and SH3 domains. The SH3 domains of ARHGEFs play an autoinhibitory role through intramolecular interactions with a proline-rich region N-terminal to the DH 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 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGERLHDQERGWFPSSMTEE 580
Cdd:cd11939    1 QVQCVHPYVSQEPDELSLELADVLNILDKTDDGWIFGERLHDQERGWFPSSVVEE 55

Ephexin Pleckstrin homology (PH) domain; Ephexin-1 (also called NGEF/ neuronal guanine nucleotide exchange factor) plays a role in the homeostatic modulation of presynaptic neurotransmitter release. Specific functions are still unknown for Ephexin-2 (also called RhoGEF19) and Ephexin-3 (also called Rho guanine nucleotide exchange factor 5/RhoGEF5, Transforming immortalized mammary oncogene/p60 TIM, and NGEF/neuronalGEF). Ephexin-4 (also called RhoGEF16) acts downstream of EphA2 to promote ligand-independent breast cancer cell migration and invasion toward epidermal growth factor through activation of RhoG. This in turn results in the activation of RhoG which recruits ELMO2 and Dock4 to form a complex with EphA2 at the tips of cortactin-rich protrusions in migrating breast cancer cells. Ephexin-5 is the specific GEF for RhoA activation and the regulation of vascular smooth muscle contractility. It interacts with EPHA4 PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. The members of the Ephexin family contains a RhoGEF (DH) followed by a PH domain and an SH3 domain. The ephexin PH domain is believed to act with the DH domain in mediating protein-protein interactions. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959 387 KIKSVPIISHSRWLLKQGELQQMSGPKTSRTLRTKKLFREIYLFLFNDLLVICRQIPGDKYQVFDSAPRGLLRVEELEDQ 466
Cdd:cd01221    1 KIKAFPLISSSRWLVKRGELTELVEDGGSLTFRKKFSKTPVYLFLFNDLLLITKKKSEERYLVLDYAPRNLVQVEEVEDP 80

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 162417959 467 GQTL----ANVFILRLLENADDREATYMLKASSQSEMKRWMTSLAPNRRTK 513
Cdd:cd01221   81 LQLPqplgKNLFLLTLLENHEGKTVELLLSAESESDRERWLSALSPPKSEL 131

Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases; Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases Also called Dbl-homologous (DH) domain. It appears that PH domains invariably occur C-terminal to RhoGEF/DH domains. Improved coverage.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959   187 AMFELVTSEASYYKSLNLLVSHFMEneRLKK---ILHPSEAHILFSNVLDVMAVSERFLLELEHRMEENIVISD-VCDIv 262
Cdd:smart00325   1 VLKELLQTERNYVRDLKLLVEVFLK--PLKKelkLLSPNELETLFGNIEEIYEFHRDFLDELEERIEEWDDSVErIGDV- 77

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959   263 YRYAADHFSVYITYVSNQTYQERTYKQLLQEKAaFRELIAQLELDPKCKGLPFSSFLILPFQRITRLKLLVQNILKRVEE 342
Cdd:smart00325  78 FLKLEEFFKIYSEYCSNHPDALELLKKLKKNPR-FQKFLKEIESSPQCRRLTLESLLLKPVQRLTKYPLLLKELLKHTPE 156

                          170       180
                   ....*....|....*....|....
gi 162417959   343 RSEREGTALDAHKELEMVVKACNE 366
Cdd:smart00325 157 DHEDREDLKKALKAIKELANQVNE 180

Src homology 3 domain of the Rho guanine nucleotide exchange factor, ephexin-1 (also called NGEF or ARHGEF27); Ephexin-1, also called NGEF (neuronal GEF) or ARHGEF27, activates RhoA, Tac1, and Cdc42 by exchanging bound GDP for free GTP. It is expressed mainly in the brain in a region associated with movement control. It regulates the stability of postsynaptic acetylcholine receptor (AChR) clusters and thus, plays a critical role in the maturation and neurotransmission of neuromuscular junctions. Ephexin-1 directly interacts with the ephrin receptor EphA4 and their coexpression enhances the ability of ephexin-1 to activate RhoA. It is required for normal axon growth and EphA-induced growth cone collapse. Ephexin-1 contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), and SH3 domains. The SH3 domains of ARHGEFs play an autoinhibitory role through intramolecular interactions with a proline-rich region N-terminal to the DH 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 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGERLHDQERGWFPSSMTEE 580
Cdd:cd11939    1 QVQCVHPYVSQEPDELSLELADVLNILDKTDDGWIFGERLHDQERGWFPSSVVEE 55

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 162417959  531 HPYVAQQPDELTLELADILNILEKTEDGWIFGERLHDQErGWFPS 575
Cdd:pfam00018   4 YDYTAQEPDELSFKKGDIIIVLEKSEDGWWKGRNKGGKE-GLIPS 47

Pleckstrin homology domain; Domain commonly found in eukaryotic signalling proteins. The domain family possesses multiple functions including the abilities to bind inositol phosphates, and various proteins. PH domains have been found to possess inserted domains (such as in PLC gamma, syntrophins) and to be inserted within other domains. Mutations in Brutons tyrosine kinase (Btk) within its PH domain cause X-linked agammaglobulinaemia (XLA) in patients. Point mutations cluster into the positively charged end of the molecule around the predicted binding site for phosphatidylinositol lipids.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959   400 LLKQGELQQMSGPKtsrtlrtKKLFREIYLFLFNDLLVICRqipgDKYQVFDSAPRGLL-----RVEELEDQGQTLA-NV 473
Cdd:smart00233   1 VIKEGWLYKKSGGG-------KKSWKKRYFVLFNSTLLYYK----SKKDKKSYKPKGSIdlsgcTVREAPDPDSSKKpHC 69

                           90       100       110
                   ....*....|....*....|....*....|...
gi 162417959   474 FILRLlenadDREATYMLKASSQSEMKRWMTSL 506
Cdd:smart00233  70 FEIKT-----SDRKTLLLQAESEEEREKWVEAL 97

Ephexin Pleckstrin homology (PH) domain; Ephexin-1 (also called NGEF/ neuronal guanine nucleotide exchange factor) plays a role in the homeostatic modulation of presynaptic neurotransmitter release. Specific functions are still unknown for Ephexin-2 (also called RhoGEF19) and Ephexin-3 (also called Rho guanine nucleotide exchange factor 5/RhoGEF5, Transforming immortalized mammary oncogene/p60 TIM, and NGEF/neuronalGEF). Ephexin-4 (also called RhoGEF16) acts downstream of EphA2 to promote ligand-independent breast cancer cell migration and invasion toward epidermal growth factor through activation of RhoG. This in turn results in the activation of RhoG which recruits ELMO2 and Dock4 to form a complex with EphA2 at the tips of cortactin-rich protrusions in migrating breast cancer cells. Ephexin-5 is the specific GEF for RhoA activation and the regulation of vascular smooth muscle contractility. It interacts with EPHA4 PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. The members of the Ephexin family contains a RhoGEF (DH) followed by a PH domain and an SH3 domain. The ephexin PH domain is believed to act with the DH domain in mediating protein-protein interactions. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959 387 KIKSVPIISHSRWLLKQGELQQMSGPKTSRTLRTKKLFREIYLFLFNDLLVICRQIPGDKYQVFDSAPRGLLRVEELEDQ 466
Cdd:cd01221    1 KIKAFPLISSSRWLVKRGELTELVEDGGSLTFRKKFSKTPVYLFLFNDLLLITKKKSEERYLVLDYAPRNLVQVEEVEDP 80

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 162417959 467 GQTL----ANVFILRLLENADDREATYMLKASSQSEMKRWMTSLAPNRRTK 513
Cdd:cd01221   81 LQLPqplgKNLFLLTLLENHEGKTVELLLSAESESDRERWLSALSPPKSEL 131

Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases; Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases Also called Dbl-homologous (DH) domain. It appears that PH domains invariably occur C-terminal to RhoGEF/DH domains. Improved coverage.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959   187 AMFELVTSEASYYKSLNLLVSHFMEneRLKK---ILHPSEAHILFSNVLDVMAVSERFLLELEHRMEENIVISD-VCDIv 262
Cdd:smart00325   1 VLKELLQTERNYVRDLKLLVEVFLK--PLKKelkLLSPNELETLFGNIEEIYEFHRDFLDELEERIEEWDDSVErIGDV- 77

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959   263 YRYAADHFSVYITYVSNQTYQERTYKQLLQEKAaFRELIAQLELDPKCKGLPFSSFLILPFQRITRLKLLVQNILKRVEE 342
Cdd:smart00325  78 FLKLEEFFKIYSEYCSNHPDALELLKKLKKNPR-FQKFLKEIESSPQCRRLTLESLLLKPVQRLTKYPLLLKELLKHTPE 156

                          170       180
                   ....*....|....*....|....
gi 162417959   343 RSEREGTALDAHKELEMVVKACNE 366
Cdd:smart00325 157 DHEDREDLKKALKAIKELANQVNE 180

Src homology 3 domain of the Rho guanine nucleotide exchange factor, ephexin-1 (also called NGEF or ARHGEF27); Ephexin-1, also called NGEF (neuronal GEF) or ARHGEF27, activates RhoA, Tac1, and Cdc42 by exchanging bound GDP for free GTP. It is expressed mainly in the brain in a region associated with movement control. It regulates the stability of postsynaptic acetylcholine receptor (AChR) clusters and thus, plays a critical role in the maturation and neurotransmission of neuromuscular junctions. Ephexin-1 directly interacts with the ephrin receptor EphA4 and their coexpression enhances the ability of ephexin-1 to activate RhoA. It is required for normal axon growth and EphA-induced growth cone collapse. Ephexin-1 contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), and SH3 domains. The SH3 domains of ARHGEFs play an autoinhibitory role through intramolecular interactions with a proline-rich region N-terminal to the DH 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 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGERLHDQERGWFPSSMTEE 580
Cdd:cd11939    1 QVQCVHPYVSQEPDELSLELADVLNILDKTDDGWIFGERLHDQERGWFPSSVVEE 55

Src homology 3 domain of the Rho guanine nucleotide exchange factors ARHGEF5 and ARHGEF19; ARHGEF5, also called ephexin-3 or TIM (Transforming immortalized mammary oncogene), is a potent activator of RhoA and it plays roles in regulating cell shape, adhesion, and migration. It binds to the SH3 domain of Src and is involved in regulating Src-induced podosome formation. ARHGEF19, also called ephexin-2 or WGEF (weak-similarity GEF), is highly expressed in the intestine, liver, heart and kidney. It activates RhoA, Cdc42, and Rac 1, and has been shown to activate RhoA in the Wnt-PCP (planar cell polarity) pathway. It is involved in the regulation of cell polarity and cytoskeletal reorganization. ARHGEF5 and ARHGEF19 contain RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), and SH3 domains. The SH3 domains of ARHGEFs play an autoinhibitory role through intramolecular interactions with a proline-rich region N-terminal to the DH 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 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGERLHDQERGWFPSSMTEE 580
Cdd:cd11940    1 QVQCIRSYKAQENDELTLEKADIIMVRQQSSDGWLEGVRLSDGERGWFPQSHVEE 55

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....
gi 162417959   523 DCPQVQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGeRLHDQERGWFPSS 576
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKG-RLGRGKEGLFPSN 53

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
                 ....*....|....*....|....*....|....*....|....*...
gi 162417959 533 YVAQQPDELTLELADILNILEKTEDGWIFGErlHDQERGWFPSSMTEE 580
Cdd:cd11766    8 YEAQREDELSLRKGDRVLVLEKSSDGWWRGE--CNGQVGWFPSNYVTE 53

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 162417959 528 QCV--HPYVAQQPDELTLELADILNILEKTEDGWIFGErLHDQeRGWFPSSMTEE 580
Cdd:cd11823    1 RCKalYSYTANREDELSLQPGDIIEVHEKQDDGWWLGE-LNGK-KGIFPATYVEE 53

Src Homology 3 domain of Insulin Receptor tyrosine kinase Substrate p53, Brain-specific Angiogenesis Inhibitor 1-Associated Protein 2 (BAIAP2)-Like proteins, and similar proteins; Proteins in this family include IRSp53, BAIAP2L1, BAIAP2L2, and similar proteins. They all contain an Inverse-Bin/Amphiphysin/Rvs (I-BAR) or IMD domain in addition to the SH3 domain. IRSp53, also known as BAIAP2, is a scaffolding protein that takes part in many signaling pathways including Cdc42-induced filopodia formation, Rac-mediated lamellipodia extension, and spine morphogenesis. IRSp53 exists as multiple splicing variants that differ mainly at the C-termini. BAIAP2L1, also called IRTKS (Insulin Receptor Tyrosine Kinase Substrate), serves as a substrate for the insulin receptor and binds the small GTPase Rac. It plays a role in regulating the actin cytoskeleton and colocalizes with F-actin, cortactin, VASP, and vinculin. IRSp53 and IRTKS also mediate the recruitment of effector proteins Tir and EspFu, which regulate host cell actin reorganization, to bacterial attachment sites. BAIAP2L2 co-localizes with clathrin plaques but its function has not been determined. The SH3 domains of IRSp53 and IRTKS have been shown to bind the proline-rich C-terminus of EspFu. 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 162417959 525 PQVQCVHPYVAQQPDELTLELADILNIL-EKTEDGWIFGERLHDQERGWFPSSMTE 579
Cdd:cd11779    1 PRVKALYPHAAGGETQLSFEEGDVITLLgPEPRDGWHYGENERSGRRGWFPIAYTE 56

Second Src Homology 3 domain (SH3B) of CD2-associated protein and similar proteins; This subfamily is composed of the second SH3 domain (SH3B) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3B of both proteins have been shown to bind to Cbl. In the case of CD2AP, its SH3B binds to Cbl at a site distinct from the c-Cbl/SH3A binding site. The CIN85 SH3B also binds ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*....
gi 162417959 532 PYVAQQPDELTLELADILNILEKTEDGWIFGeRLHDQErGWFPSSMTEE 580
Cdd:cd11874    7 SYTPQNEDELELKVGDTIEVLGEVEEGWWEG-KLNGKV-GVFPSNFVKE 53

Second Src homology 3 domain (or SH3B) of Intersectin; Intersectins (ITSNs) are adaptor proteins that function in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. They are essential for initiating clathrin-coated pit formation. They bind to many proteins through their multidomain structure and facilitate the assembly of multimeric complexes. Vertebrates contain two ITSN proteins, ITSN1 and ITSN2, which exist in alternatively spliced short and long isoforms. The short isoforms contain two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoforms, in addition, contain RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. ITSN1 and ITSN2 are both widely expressed, with variations depending on tissue type and stage of development. The second SH3 domain (or SH3B) of ITSN1 has been shown to bind WNK and CdGAP. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDgWIFGErLHDQERGWFPSS 576
Cdd:cd11837    1 TATALYPWRAKKENHLSFAKGDIITVLEQQEM-WWFGE-LEGGEEGWFPKS 49

RhoGEF, Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases [Signal transduction mechanisms];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959  173 VLDILQPEEIRLQEAMFELVTSEASYYKSLNLLVSHFM----------ENERLKKILHpseahiLFSNVLDVMAVSERFL 242
Cdd:COG5422   474 VWESLPKQEIKRQEAIYEVIYTERDFVKDLEYLRDTWIkpleesniipENARRNFIKH------VFANINEIYAVNSKLL 547

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959  243 LELEHRMEENIVISDVCDIVYRYAAdHFSVYITYVSNQTYQER---TYKQLLQEKAAFRELIAQLElDPKCKGLpfSSFL 319
Cdd:COG5422   548 KALTNRQCLSPIVNGIADIFLDYVP-KFEPFIKYGASQPYAKYefeREKSVNPNFARFDHEVERLD-ESRKLEL--DGYL 623

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959  320 ILPFQRITRLKLLVQNILKRVEERSEREGTALDAHKELEMVVKACNEGVRKMSRTEQMISIQKKMEFKIKSVPI--ISHS 397
Cdd:COG5422   624 TKPTTRLARYPLLLEEVLKFTDPDNPDTEDIPKVIDMLREFLSRLNFESGKAENRGDLFHLNQQLLFKPEYVNLglNDEY 703

                         250       260       270       280
                  ....*....|....*....|....*....|....*....|...
gi 162417959  398 RWLLKQGELQQMSGPKTSRTLRTkklfrEIYLFLFNDLLVICR 440
Cdd:COG5422   704 RKIIFKGVLKRKAKSKTDGSLRG-----DIQFFLLDNMLLFCK 741

Pleckstrin homology domain-containing family G member 5 and 6 pleckstrin homology (PH) domain; PLEKHG5 has a RhoGEF DH/double-homology domain in tandem with a PH domain which is involved in phospholipid binding. PLEKHG5 activates the nuclear factor kappa B (NFKB1) signaling pathway. Mutations in PLEKHG5 are associated with autosomal recessive distal spinal muscular atrophy. PLEKHG6 (also called MyoGEF) has no known function to date. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959 398 RWLLKQGELQQMSGpKTSRTlrtkklfrEIYLFLFNDLLVICRQI--PGDKYQVFdsapRGLLRVEELEDQGQTLANVFI 475
Cdd:cd13244    1 RRLLLEGDLRLKEG-KGSKV--------DVHCFLFTDMLLICKPVkrKKDRLKVI----RPPYLVDKLVVQELKDPGGFL 67

                         90       100       110
                 ....*....|....*....|....*....|..
gi 162417959 476 LRLLENADDREATYMLKASSQSEMKRWMTSLA 507
Cdd:cd13244   68 LVYLNEFHTAVAAYTFQTSSQEDTRRWLDAIR 99

FYVE, RhoGEF and PH domain containing/faciogenital dysplasia proteins 1-4 and similar proteins, N-terminal Pleckstrin homology (PH) domain; In general, FGDs have a RhoGEF (DH) domain, followed by an N-terminal PH domain, a FYVE domain and a C-terminal PH domain. All FGDs are guanine nucleotide exchange factors that activates the Rho GTPase Cdc42, an important regulator of membrane trafficking. The RhoGEF domain is responsible for GEF catalytic activity, while the N-terminal PH domain is involved in intracellular targeting of the DH domain. Mutations in the FGD1 gene are responsible for the X-linked disorder known as faciogenital dysplasia (FGDY). Both FGD1 and FGD3 are targeted by the ubiquitin ligase SCF(FWD1/beta-TrCP) upon phosphorylation of two serine residues in its DSGIDS motif and subsequently degraded by the proteasome. They play different roles to regulate cellular functions, even though their intracellular levels are tightly controlled by the same destruction pathway. FGD4 is one of the genes associated with Charcot-Marie-Tooth neuropathy type 4 (CMT4), a group of progressive motor and sensory axonal and demyelinating neuropathies that are distinguished from other forms of CMT by autosomal recessive inheritance. Those affected have distal muscle weakness and atrophy associated with sensory loss and, frequently, pes cavus foot deformity. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959 400 LLKQGELQQMSgpktSRTLRTKklfrEIYLFLFNDLLVIC--RQIP-GDKYQVfdsapRGLLRVEEL---EDQGQTLANV 473
Cdd:cd13388    1 LIKEGKILKIS----ARNGDTQ----ERYLFLFNDMLLYCspRLRLiGQKYKV-----RARFDVDGMqvlEGDNLETPHT 67

                         90       100       110
                 ....*....|....*....|....*....|...
gi 162417959 474 FILRllenadDREATYMLKASSQSEMKRWMTSL 506
Cdd:cd13388   68 FYVR------GKQRSLELQASTQEEKAEWVDAI 94

Src Homology 3 domain of Pak Interactive eXchange factors; PIX proteins are Rho guanine nucleotide exchange factors (GEFs), which activate small GTPases by exchanging bound GDP for free GTP. They act as GEFs for both Cdc42 and Rac 1, and have been implicated in cell motility, adhesion, neurite outgrowth, and cell polarity. Vertebrates contain two proteins from the PIX subfamily, alpha-PIX and beta-PIX. Alpha-PIX, also called ARHGEF6, is localized in dendritic spines where it regulates spine morphogenesis. Mutations in the ARHGEF6 gene cause X-linked intellectual disability in humans. Beta-PIX play roles in regulating neuroendocrine exocytosis, focal adhesion maturation, cell migration, synaptic vesicle localization, and insulin secretion. PIX proteins contain an N-terminal SH3 domain followed by RhoGEF (also called Dbl-homologous or DH) and Pleckstrin Homology (PH) domains, and a C-terminal leucine-zipper domain for dimerization. The SH3 domain of PIX binds to an atypical PxxxPR motif in p21-activated kinases (PAKs) with high affinity. The binding of PAKs to PIX facilitate the localization of PAKs to focal complexes and also localizes PAKs to PIX targets Cdc43 and Rac, leading to the activation of PAKs. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDGWifGERLHDQERGWFPSSMTEE 580
Cdd:cd11877    1 LVRAKFNFEGTNEDELSFDKGDIITVTQVVEGGW--WEGTLNGKTGWFPSNYVKE 53

Fifth Src homology 3 domain (or SH3E) 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 fifth SH3 domain (or SH3E) of ITSN1 has been shown to bind many protein partners including SGIP1, Sos1, dynamin1/2, CIN85, c-Cbl, SHIP2, N-WASP, and synaptojanin-1, 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 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGErLHDQErGWFPSSMTEE 580
Cdd:cd11840    1 QVIALFPYTAQNEDELSFQKGDIINVLSKDDPDWWRGE-LNGQT-GLFPSNYVEP 53

First Src homology 3 domain (or SH3A) of Intersectin-2; Intersectin-2 (ITSN2) 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. ITSN2 also functions as a specific GEF for Cdc42 activation in epithelial morphogenesis, and is required in mitotic spindle orientation. 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 first SH3 domain (or SH3A) of ITSN2 is expected to bind many protein partners, similar to ITSN1 which has been shown to bind Sos1, dynamin1/2, CIN85, c-Cbl, PI3K-C2, SHIP2, N-WASP, and CdGAP, 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 162417959 530 VHPYVAQQPDELTLELADILNILEKT--EDGWIFGErlHDQERGWFPSSMTEE 580
Cdd:cd11988    7 LYPFEARNHDEMSFNAGDIIQVDEKTvgEPGWLYGS--FQGNFGWFPCNYVEK 57

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 162417959 526 QVQCVHPYVAQQPDELTLELADILNIL-EKTEDGWIFGERLHDqERGWFPSSMTEE 580
Cdd:cd11763    1 KVRALYDFDSQPSGELSLRAGEVLTITrQDVGDGWLEGRNSRG-EVGLFPSSYVEI 55

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

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 162417959 533 YVAQQPDELTLELADILNILEK-TED-GWIFGErlHDQERGWFP 574
Cdd:cd12142    8 YNPVAPDELALKKGDVIEVISKeTEDeGWWEGE--LNGRRGFFP 49

FYVE, RhoGEF and PH domain containing/faciogenital dysplasia proteins 5 and 6, N-terminal Pleckstrin Homology (PH) domain; FGD5 regulates promotes angiogenesis of vascular endothelial growth factor (VEGF) in vascular endothelial cells, including network formation, permeability, directional movement, and proliferation. The specific function of FGD6 is unknown. In general, FGDs have a RhoGEF (DH) domain, followed by a PH domain, a FYVE domain and a C-terminal PH domain. All FGDs are guanine nucleotide exchange factors that activate the Rho GTPase Cdc42, an important regulator of membrane trafficking. The RhoGEF domain is responsible for GEF catalytic activity, while the PH domain is involved in intracellular targeting of the DH domain. PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959 393 IISHSRWLLKQGELQqmsgpKTSRtlrtkKLFREIYLFLFNDLLVICRQIPGD-KYQVFDSAPRGLLRVEELEDqgQTLA 471
Cdd:cd13389    7 IVKPGRKLIKEGELM-----KVSR-----KEMQPRYFFLFNDCLLYTTPVQSSgMLKLNNELPLSGMKVKLPED--EEYS 74

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*....
gi 162417959 472 NVFILRllenadDREATYMLKASSQSEMKRWMTSL---APNRRTKFVSF 517
Cdd:cd13389   75 NEFQII------STKRSFTLIASSEEERDEWVKALsraIEEHTKKQRTF 117

PH domain; PH stands for pleckstrin homology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959  400 LLKQGELQQMSGPKtsrtlrtKKLFREIYLFLFNDLLVICRQIPGDKyqvfDSAPRGLLRVEELEDQ----GQTLANVFI 475
Cdd:pfam00169   1 VVKEGWLLKKGGGK-------KKSWKKRYFVLFDGSLLYYKDDKSGK----SKEPKGSISLSGCEVVevvaSDSPKRKFC 69

                          90       100       110
                  ....*....|....*....|....*....|.
gi 162417959  476 LRLLENADDREATYMLKASSQSEMKRWMTSL 506
Cdd:pfam00169  70 FELRTGERTGKRTYLLQAESEEERKDWIKAI 100

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        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 162417959 526 QVQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGeRLHDQErGWFPSSMTEE 580
Cdd:cd11827    1 QCKALYAYDAQDTDELSFNEGDIIEILKEDPSGWWTG-RLRGKE-GLFPGNYVEK 53

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|.
gi 162417959 532 PYVAQQPDELTLELADILNILEKT-ED-GWIFGERlhDQERGWFPSSMTEE 580
Cdd:cd11875    7 DYEAENEDELTLREGDIVTILSKDcEDkGWWKGEL--NGKRGVFPDNFVEP 55

Pleckstrin homology (PH) domain; PH domains have diverse functions, but in general are involved in targeting proteins to the appropriate cellular location or in the interaction with a binding partner. They share little sequence conservation, but all have a common fold, which is electrostatically polarized. Less than 10% of PH domains bind phosphoinositide phosphates (PIPs) with high affinity and specificity. PH domains are distinguished from other PIP-binding domains by their specific high-affinity binding to PIPs with two vicinal phosphate groups: PtdIns(3,4)P2, PtdIns(4,5)P2 or PtdIns(3,4,5)P3 which results in targeting some PH domain proteins to the plasma membrane. A few display strong specificity in lipid binding. Any specificity is usually determined by loop regions or insertions in the N-terminus of the domain, which are not conserved across all PH domains. PH domains are found in cellular signaling proteins such as serine/threonine kinase, tyrosine kinases, regulators of G-proteins, endocytotic GTPases, adaptors, as well as cytoskeletal associated molecules and in lipid associated enzymes.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 162417959 402 KQGELQQMSGPktsrtlrTKKLFREIYLFLFNDLLVICRQIPGDKYQVFDSAP-RGLLRVEELEDQGQtlANVFILRLLE 480
Cdd:cd00821    1 KEGYLLKRGGG-------GLKSWKKRWFVLFEGVLLYYKSKKDSSYKPKGSIPlSGILEVEEVSPKER--PHCFELVTPD 71

                         90       100
                 ....*....|....*....|....*.
gi 162417959 481 naddrEATYMLKASSQSEMKRWMTSL 506
Cdd:cd00821   72 -----GRTYYLQADSEEERQEWLKAL 92

Src Homology 3 domain of Abelson helper integration site-1 (AHI-1); AHI-1, also called Jouberin, is expressed in high levels in the brain, gonad tissues, and skeletal muscle. It is an adaptor protein that interacts with the small GTPase Rab8a and regulates it distribution and function, affecting cilium formation and vesicle transport. Mutations in the AHI-1 gene can cause Joubert syndrome, a disorder characterized by brainstem malformations, cerebellar aplasia/hypoplasia, and retinal dystrophy. AHI-1 variation is also associated with susceptibility to schizophrenia and type 2 diabetes mellitus progression. AHI-1 contains WD40 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        50
                 ....*....|....*....|....*....|....*....|....*....|
gi 162417959 527 VQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGERLHDQErGWFPSS 576
Cdd:cd11812    2 VVALYDYTANRSDELTIHRGDIIRVLYKDNDNWWFGSLVNGQQ-GYFPAN 50

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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*..
gi 162417959 530 VHPYVAQQPDELTLELADILNILEKTEDGWIFGERLHDQERGWFPSS 576
Cdd:cd11926    5 IYPYTPRKEDELELRKGEMFLVFERCQDGWFKGTSMHTSKIGVFPGN 51

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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*..
gi 162417959 526 QVQCVHPYVA-QQPDELTLELADILNILEKTEDGWIFGERLHDQERGWFPSSMTEEI 581
Cdd:cd11788    3 RVRAILPYNKvPDTDELSFQKGDIFVVHNELEDGWLWVTSLRTGESGLVFRDLVEEL 59

Second Src Homology 3 domain (SH3B) 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 second SH3 domain (SH3B) of CIN85. SH3B has been shown to bind Cbl proline-rich peptides and 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|...
gi 162417959 528 QCVHPYVAQQPDELTLELADILNILEKTEDGWifGERLHDQERGWFPSSMTEE 580
Cdd:cd12055    3 QVAFSYLPQNEDELELKVGDIIEVVGEVEEGW--WEGVLNGKTGMFPSNFIKE 53

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 162417959 527 VQCVHPYVAQQPDELTLELADILNILEKTEDGWiFGERLHDQErGWFPSSMTEE 580
Cdd:cd11772    2 FRALYDYEAQHPDELSFEEGDLLYISDKSDPNW-WKATCGGKT-GLIPSNYVEE 53

Src homology 3 domain of Phospholipase C (PLC) gamma 1; PLCgamma1 is widely expressed and is essential in growth and development. It is activated by the TrkA receptor tyrosine kinase and functions as a key regulator of cell differentiation. It is also the predominant PLCgamma in T cells and is required for T cell and NK cell function. PLCs catalyze the hydrolysis of phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] to produce Ins(1,4,5)P3 and diacylglycerol (DAG). Ins(1,4,5)P3 initiates the calcium signaling cascade while DAG functions as an activator of PKC. PLCgamma contains a Pleckstrin homology (PH) domain followed by an elongation factor (EF) domain, two catalytic regions of PLC domains that flank two tandem SH2 domains, followed by a SH3 domain and C2 domain. The SH3 domain of PLCgamma1 directly interacts with dynamin-1 and can serve as a guanine nucleotide exchange factor (GEF). It also interacts with Cbl, inhibiting its phosphorylation and activity. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 162417959 527 VQCVHPYVAQQPDELTLELADILNILEKTEDGWIFGErLHDQERGWFPSSMTEEIL 582
Cdd:cd11970    6 VKALFDYKAQREDELTFTKNAIIQNVEKQEGGWWRGD-YGGKKQLWFPSNYVEEIS 60