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 166197690 385 KIKSVPIISHSRWLLKQGELQQMSGPKTSRTLRTKKLFHEIYLFLFNDLLVICRQIPGDKYQVFDSAPRGLLRVEELEDQ 464
Cdd:cd01221    1 KIKAFPLISSSRWLVKRGELTELVEDGGSLTFRKKFSKTPVYLFLFNDLLLITKKKSEERYLVLDYAPRNLVQVEEVEDP 80

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 166197690 465 GQTL----ANVFILRLLENADDREATYMLKASSQSEMKRWMTSLAPNRRTK 511
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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGERLHDQERGWFPSSMTEE 578
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 166197690 385 KIKSVPIISHSRWLLKQGELQQMSGPKTSRTLRTKKLFHEIYLFLFNDLLVICRQIPGDKYQVFDSAPRGLLRVEELEDQ 464
Cdd:cd01221    1 KIKAFPLISSSRWLVKRGELTELVEDGGSLTFRKKFSKTPVYLFLFNDLLLITKKKSEERYLVLDYAPRNLVQVEEVEDP 80

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 166197690 465 GQTL----ANVFILRLLENADDREATYMLKASSQSEMKRWMTSLAPNRRTK 511
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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGERLHDQERGWFPSSMTEE 578
Cdd:cd11939    1 QVQCVHPYVSQEPDELSLELADVLNILDKTDDGWIFGERLHDQERGWFPSSVVEE 55

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.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 166197690 182 LQEAMFELVTSEASYYKSLNLLVSHFMEN-ERIRKILHPSEAHILFSNVLDVLAVSERFLLELEHRMEENIVISD-VCDi 259
Cdd:cd00160    1 RQEVIKELLQTERNYVRDLKLLVEVFLKPlDKELLPLSPEEVELLFGNIEEIYEFHRIFLKSLEERVEEWDKSGPrIGD- 79

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 166197690 260 VYRYAADHFSVYITYVSNQTYQERTYKQLLQEKAAFRELIAQLELdpKCRGLPFSSFLILPFQRITRLKLLVQNILKRVE 339
Cdd:cd00160   80 VFLKLAPFFKIYSEYCSNHPDALELLKKLKKFNKFFQEFLEKAES--ECGRLKLESLLLKPVQRLTKYPLLLKELLKHTP 157

                        170       180
                 ....*....|....*....|....
gi 166197690 340 ERSERECTALDAHKELEMVVKACN 363
Cdd:cd00160  158 DGHEDREDLKKALEAIKEVASQVN 181

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 166197690  529 HPYVAQQPDELTLELADILNILDKTDDGWIFGERLHDQErGWFPS 573
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 166197690   398 LLKQGELQQMSGPKtsrtlrtKKLFHEIYLFLFNDLLVICRqipgDKYQVFDSAPRGLL-----RVEELEDQGQTLA-NV 471
Cdd:smart00233   1 VIKEGWLYKKSGGG-------KKSWKKRYFVLFNSTLLYYK----SKKDKKSYKPKGSIdlsgcTVREAPDPDSSKKpHC 69

                           90       100       110
                   ....*....|....*....|....*....|...
gi 166197690   472 FILRLlenadDREATYMLKASSQSEMKRWMTSL 504
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 166197690 385 KIKSVPIISHSRWLLKQGELQQMSGPKTSRTLRTKKLFHEIYLFLFNDLLVICRQIPGDKYQVFDSAPRGLLRVEELEDQ 464
Cdd:cd01221    1 KIKAFPLISSSRWLVKRGELTELVEDGGSLTFRKKFSKTPVYLFLFNDLLLITKKKSEERYLVLDYAPRNLVQVEEVEDP 80

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|.
gi 166197690 465 GQTL----ANVFILRLLENADDREATYMLKASSQSEMKRWMTSLAPNRRTK 511
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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGERLHDQERGWFPSSMTEE 578
Cdd:cd11939    1 QVQCVHPYVSQEPDELSLELADVLNILDKTDDGWIFGERLHDQERGWFPSSVVEE 55

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.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 166197690 182 LQEAMFELVTSEASYYKSLNLLVSHFMEN-ERIRKILHPSEAHILFSNVLDVLAVSERFLLELEHRMEENIVISD-VCDi 259
Cdd:cd00160    1 RQEVIKELLQTERNYVRDLKLLVEVFLKPlDKELLPLSPEEVELLFGNIEEIYEFHRIFLKSLEERVEEWDKSGPrIGD- 79

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 166197690 260 VYRYAADHFSVYITYVSNQTYQERTYKQLLQEKAAFRELIAQLELdpKCRGLPFSSFLILPFQRITRLKLLVQNILKRVE 339
Cdd:cd00160   80 VFLKLAPFFKIYSEYCSNHPDALELLKKLKKFNKFFQEFLEKAES--ECGRLKLESLLLKPVQRLTKYPLLLKELLKHTP 157

                        170       180
                 ....*....|....*....|....
gi 166197690 340 ERSERECTALDAHKELEMVVKACN 363
Cdd:cd00160  158 DGHEDREDLKKALEAIKEVASQVN 181

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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGERLHDQERGWFPSSMTEE 578
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 166197690   521 DCPQVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGeRLHDQERGWFPSS 574
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 166197690 531 YVAQQPDELTLELADILNILDKTDDGWIFGErlHDQERGWFPSSMTEE 578
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 166197690 526 QCV--HPYVAQQPDELTLELADILNILDKTDDGWIFGErLHDQeRGWFPSSMTEE 578
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 166197690 523 PQVQCVHPYVAQQPDELTLELADILNIL-DKTDDGWIFGERLHDQERGWFPSSMTE 577
Cdd:cd11779    1 PRVKALYPHAAGGETQLSFEEGDVITLLgPEPRDGWHYGENERSGRRGWFPIAYTE 56

Fourth Src homology 3 domain (or SH3D) 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 fourth SH3 domain (or SH3D) of ITSN1 has been shown to bind SHIP2, Numb, CdGAP, and N-WASP. 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 166197690 526 QCVHPYVAQQPDELTLELADILNILDKTDDGWIFGE---RLHDQERGWFPSS 574
Cdd:cd11839    3 QVIAPFTATAENQLSLAVGQLVLVRKKSPSGWWEGElqaRGKKRQIGWFPAN 54

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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGErLHDQErGWFPSSMTEE 578
Cdd:cd11840    1 QVIALFPYTAQNEDELSFQKGDIINVLSKDDPDWWRGE-LNGQT-GLFPSNYVEP 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 166197690 530 PYVAQQPDELTLELADILNILDKT--DDGWIFGERlhDQERGWFPSSMTEE 578
Cdd:cd11875    7 DYEAENEDELTLREGDIVTILSKDceDKGWWKGEL--NGKRGVFPDNFVEP 55

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 166197690   398 LLKQGELQQMSGPKtsrtlrtKKLFHEIYLFLFNDLLVICRqipgDKYQVFDSAPRGLL-----RVEELEDQGQTLA-NV 471
Cdd:smart00233   1 VIKEGWLYKKSGGG-------KKSWKKRYFVLFNSTLLYYK----SKKDKKSYKPKGSIdlsgcTVREAPDPDSSKKpHC 69

                           90       100       110
                   ....*....|....*....|....*....|...
gi 166197690   472 FILRLlenadDREATYMLKASSQSEMKRWMTSL 504
Cdd:smart00233  70 FEIKT-----SDRKTLLLQAESEEEREKWVEAL 97

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 166197690 531 YVAQQPDELTLELADILNILDKT--DDGWIFGErlHDQERGWFP 572
Cdd:cd12142    8 YNPVAPDELALKKGDVIEVISKEteDEGWWEGE--LNGRRGFFP 49

Src Homology 3 domain of Sdc25/Cdc25 guanine nucleotide exchange factors; This subfamily is composed of the Saccharomyces cerevisiae guanine nucleotide exchange factors (GEFs) Sdc25 and Cdc25, and similar proteins. These GEFs regulate Ras by stimulating the GDP/GTP exchange on Ras. Cdc25 is involved in the Ras/PKA pathway that plays an important role in the regulation of metabolism, stress responses, and proliferation, depending on available nutrients and conditions. Proteins in this subfamily contain an N-terminal SH3 domain as well as REM (Ras exchanger motif) and RasGEF domains at the C-terminus. 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 166197690 525 VQCVHPYVAQQPDELTLELADILNILDKTDDGW---IFGERLHDQERGWFPSS 574
Cdd:cd11883    2 VVALYDFTPKSKNQLSFKAGDIIYVLNKDPSGWwdgVIISSSGKVKRGWFPSN 54

Variant SH3 domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 166197690  528 VHPYVAQQPDELTLELADILNILDKTDDGWIFGERlhDQERGWFPSSMTE 577
Cdd:pfam14604   2 LYPYEPKDDDELSLQRGDVITVIEESEDGWWEGIN--TGRTGLVPANYVE 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 166197690 391 IISHSRWLLKQGELQqmsgpKTSRtlrtkKLFHEIYLFLFNDLLVICRQIPGD-KYQVFDSAPRGLLRVEELEDqgQTLA 469
Cdd:cd13389    7 IVKPGRKLIKEGELM-----KVSR-----KEMQPRYFFLFNDCLLYTTPVQSSgMLKLNNELPLSGMKVKLPED--EEYS 74

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*....
gi 166197690 470 NVFILRllenadDREATYMLKASSQSEMKRWMTSL---APNRRTKFVSF 515
Cdd:cd13389   75 NEFQII------STKRSFTLIASSEEERDEWVKALsraIEEHTKKQRTF 117

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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDgWIFGErLHDQERGWFPSS 574
Cdd:cd11837    1 TATALYPWRAKKENHLSFAKGDIITVLEQQEM-WWFGE-LEGGEEGWFPKS 49

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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWifGERLHDQERGWFPSSMTEE 578
Cdd:cd11877    1 LVRAKFNFEGTNEDELSFDKGDIITVTQVVEGGW--WEGTLNGKTGWFPSNYVKE 53

Src Homology 3 domain of Brain-specific Angiogenesis Inhibitor 1-Associated Protein 2-Like 1, also called Insulin Receptor Tyrosine Kinase Substrate (IRTKS); BAIAP2L1 or IRTKS is widely expressed, 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. BAIAP2L1 expression leads to the formation of short actin bundles, distinct from filopodia-like protrusions induced by the expression of the related protein IRSp53. IRTKS mediates the recruitment of effector proteins Tir and EspFu, which regulate host cell actin reorganization, to bacterial attachment sites. It contains an N-terminal IMD or Inverse-Bin/Amphiphysin/Rvs (I-BAR) domain, an SH3 domain, and a WASP homology 2 (WH2) actin-binding motif at the C-terminus. The SH3 domain of IRTKS has 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 166197690 524 QVQCVHPYVA-QQPDELTLELADILNIL-DKTDDGWIFGERLHDQERGWFPSSMT 576
Cdd:cd11913    2 KVKTIFPHTAgNNKTLLSFAQGDVITLLiPEEKDGWLYGEHDTTKARGWFPSSYT 56

First Src Homology 3 domain (SH3A) of CD2-associated protein and similar proteins; This subfamily is composed of the first SH3 domain (SH3A) of CD2AP, CIN85 (Cbl-interacting protein of 85 kDa), and similar domains. CD2AP and CIN85 are adaptor proteins that bind to protein partners and assemble complexes that have been implicated in T cell activation, kidney function, and apoptosis of neuronal cells. They also associate with endocytic proteins, actin cytoskeleton components, and other adaptor proteins involved in receptor tyrosine kinase (RTK) signaling. CD2AP and the main isoform of CIN85 contain three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP and CIN85 to bind various protein partners and assemble complexes that have been implicated in many different functions. SH3A of both proteins bind to an atypical PXXXPR motif at the C-terminus of Cbl and the cytoplasmic domain of the cell adhesion protein CD2. CIN85 SH3A binds to internal proline-rich motifs within the proline-rich region; this intramolecular interaction serves as a regulatory mechanism to keep CIN85 in a closed conformation, preventing the recruitment of other proteins. CIN85 SH3A has also been shown to bind ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....
gi 166197690 529 HPYVAQQPDELTLELADILNILDKTDDGWIFGErLHDQeRGWFP 572
Cdd:cd11873    6 FDYDAEEPDELTLKVGDIITNVKKMEEGWWEGT-LNGK-RGMFP 47

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 166197690 525 VQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGERLHDQErGWFPSS 574
Cdd:cd11812    2 VVALYDYTANRSDELTIHRGDIIRVLYKDNDNWWFGSLVNGQQ-GYFPAN 50

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 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGeRLHDQErGWFPSSMTEE 578
Cdd:cd11827    1 QCKALYAYDAQDTDELSFNEGDIIEILKEDPSGWWTG-RLRGKE-GLFPGNYVEK 53

Second Src Homology 3 domain (SH3B) of CD2-associated protein; CD2AP, also called CMS (Cas ligand with Multiple SH3 domains) or METS1 (Mesenchyme-to-Epithelium Transition protein with SH3 domains), is a cytosolic adaptor protein that plays a role in regulating the cytoskeleton. It is critical in cell-to-cell union necessary for kidney function. It also stabilizes the contact between a T cell and antigen-presenting cells. It is primarily expressed in podocytes at the cytoplasmic face of the slit diaphragm and serves as a linker anchoring podocin and nephrin to the actin cytoskeleton. CD2AP contains three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP 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 CD2AP. SH3B binds to c-Cbl in a site (TPSSRPLR is the core binding motif) distinct from the c-Cbl/SH3A binding site. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGErlHDQERGWFPSSMTEEI 579
Cdd:cd12054    2 QCKVLFEYVPQNEDELELKVGDIIDINEEVEEGWWSGT--LNGKSGLFPSNFVKEL 55

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.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|....*...
gi 166197690 531 YVAQQPDELTLELADILNILDKTDDGWIFGERlhDQERGWFPSSMTEE 578
Cdd:cd12052    8 YKAQHEDELTITVGDIITKIKKDDGGWWEGEI--KGRRGLFPDNFVRE 53

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
                 ....*....|....*....|....*....|....*....|....*
gi 166197690 528 VHPYVAQQPDELTLELADILNILDKTDDGWIFGERLHDQERGWFP 572
Cdd:cd11918    7 VYQYRPQNEDELELREGDRVDVMQQCDDGWFVGVSRRTQKFGTFP 51

First Src homology 3 domain of Tyrosine kinase substrate (Tks) proteins; Tks proteins are Src substrates and scaffolding proteins that play important roles in the formation of podosomes and invadopodia, the dynamic actin-rich structures that are related to cell migration and cancer cell invasion. Vertebrates contain two Tks proteins, Tks4 (Tyr kinase substrate with four SH3 domains) and Tks5 (Tyr kinase substrate with five SH3 domains), which display partially overlapping but non-redundant functions. Both associate with the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. Tks5 interacts with N-WASP and Nck, while Tks4 is essential for the localization of MT1-MMP (membrane-type 1 matrix metalloproteinase) to invadopodia. Tks proteins contain an N-terminal Phox homology (PX) domain and four or five SH3 domains. This model characterizes the first SH3 domain of Tks proteins. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....
gi 166197690 524 QVQCVHPYVAQQPDELTLELADILNILDKTDDGWIFGErLHDqERGWFPSSMTE 577
Cdd:cd12015    1 QYVVVADYKKQQPNEISLRAGDVVDVIEKNENGWWFVS-LED-EQGWVPATYLE 52

Src Homology 3 domain of Bridging integrator 1 (Bin1), also called Amphiphysin-2; Bin1 isoforms are localized in many different tissues and may function in intracellular vesicle trafficking. It plays a role in the organization and maintenance of the T-tubule network in skeletal muscle. Mutations in Bin1 are associated with autosomal recessive centronuclear myopathy. Bin1 contains an N-terminal BAR domain with an additional N-terminal amphipathic helix (an N-BAR) and a C-terminal SH3 domain. The SH3 domain of Bin1 forms transient complexes with actin, myosin filaments, and CDK5, to facilitate sarcomere organization and myofiber maturation. It also binds dynamin and prevents its self-assembly. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 166197690 524 QVQCVHPYVAQQPDELTLELADILNIL-----DKTDDGWIFGERLHD--------QERGWFPSSMTEEI 579
Cdd:cd12139    4 KVQAQHDYTATDTDELQLKAGDVVLVIpfqnpEEQDEGWLMGVKESDwnqhkkleKCRGVFPENFTERV 72

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 166197690 528 VHPYVAQQPDELTLELADILNILDKT--DDGWIFGErlHDQERGWFPSSMTEE 578
Cdd:cd11988    7 LYPFEARNHDEMSFNAGDIIQVDEKTvgEPGWLYGS--FQGNFGWFPCNYVEK 57

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

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 166197690 527 CVHPYVAQQPDELTLELADILNILDKTDDGWIFGeRLHDQERGWFPSSMTEE 578
Cdd:cd11795    4 CIEAFTSQEPGHLNLQRGDLVELTGTTDSGWLQG-RSCWGSSGFFPSSCVQE 54