Cloned out of library/PAK-interactive exchange factor pleckstrin homology (PH) domain; There are two forms of Pix proteins: alpha Pix (also called Rho guanine nucleotide exchange factor (GEF) 6/90Cool-2) and beta Pix (GEF7/p85Cool-1). betaPix contains an N-terminal SH3 domain, a RhoGEF/DH domain, a PH domain, a GIT1 binding domain (GBD), and a C-terminal coiled-coil (CC) domain. alphaPix differs in that it contains a calponin homology (CH) domain, which interacts with beta-parvin, N-terminal to the SH3 domain. alphaPix is an exchange factor for Rac1 and Cdc42 and mediates Pak activation on cell adhesion to fibronectin. Mutations in alphaPix can cause X-linked mental retardation. alphaPix also interacts with Huntington's disease protein (htt), and enhances the aggregation of mutant htt (muthtt) by facilitating SDS-soluble muthtt-muthtt interactions. The DH-PH domain of a Pix was required for its binding to htt. In the majority of Rho GEF proteins, the DH-PH domain is responsible for the exchange activity. 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 1622884655 387 VTYMSQVLIQCAGSEEKNERYLLLFPNVLLMLSASPRMSGFIYQGKLPTTGMTITKLEDSENHRNAFEISgdrhklcecr 466
Cdd:cd01225     1 VIHMSQVAVQNTGCQEKKERYFLLFPHVLLMLSASPRMSGFIYEGKLPLTGISVNRLEDTEGIKNAFEIS---------- 70

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*....
gi 1622884655 467 vsgrrgslspradsclhiseGSMIERILVSCNNQQDLQEWVDHLQKQTK 515
Cdd:cd01225    71 --------------------GPLIERIVVICNSQQDQQEWLEHLQQQTK 99

betaPIX coiled coil; betaPIX_CC is the very C-terminal coiled-coil region of betaPIX or p21-activated kinase interacting exchange factor proteins. The coiled-coil runs from residues 589-646 in UniProtKB:G31IU6, and the PDZ-binding site is the final eight residues immediately downstream. The coiled-coil trimerizes and thus exposes three potential PZD-binding surfaces, although only one of these is maximally used. One of the C-terminal ends of the coiled-coil forms an extensive beta-sheet interaction with the Shank PDZ, while the other two ends are not involved in ligand binding and form random coils. Thus the coiled-coil domain allows multimerization of betaPIX that is vital for its physiological functions. betaPIX and the Shank/ProSAP protein form a complex that acts as a protein scaffold for integrating signalling pathways and regulating postsynaptic structure.** Forced reload

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 735 APQVLLPEEEKIIVEETKSNgQTVIEEKSLVDTVYALKDEVQELRQDNKKMKKSLEEEQRARKDLEKLVRKVLKNMNDPA 814
Cdd:pfam16523   1 QPHVLVPEEEKIIVEETKSN-QTVLQEKSLVDAVYALKDEVQELKQENKKMKKSLEEEQKARRRLEKVVRKLLKSINDPG 79

                  ....*
gi 1622884655 815 WDETN 819
Cdd:pfam16523  80 WDETN 84

Src Homology 3 domain of beta-Pak Interactive eXchange factor; Beta-PIX, also called Rho guanine nucleotide exchange factor 7 (ARHGEF7) or Cool (Cloned out of Library)-1, activates small GTPases by exchanging bound GDP for free GTP. It acts as a GEF for both Cdc42 and Rac 1, and plays important 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 1622884655  95 VVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVREV 148
Cdd:cd12061     1 VVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTHNGRTGWFPSNYVREI 54

Cloned out of library/PAK-interactive exchange factor pleckstrin homology (PH) domain; There are two forms of Pix proteins: alpha Pix (also called Rho guanine nucleotide exchange factor (GEF) 6/90Cool-2) and beta Pix (GEF7/p85Cool-1). betaPix contains an N-terminal SH3 domain, a RhoGEF/DH domain, a PH domain, a GIT1 binding domain (GBD), and a C-terminal coiled-coil (CC) domain. alphaPix differs in that it contains a calponin homology (CH) domain, which interacts with beta-parvin, N-terminal to the SH3 domain. alphaPix is an exchange factor for Rac1 and Cdc42 and mediates Pak activation on cell adhesion to fibronectin. Mutations in alphaPix can cause X-linked mental retardation. alphaPix also interacts with Huntington's disease protein (htt), and enhances the aggregation of mutant htt (muthtt) by facilitating SDS-soluble muthtt-muthtt interactions. The DH-PH domain of a Pix was required for its binding to htt. In the majority of Rho GEF proteins, the DH-PH domain is responsible for the exchange activity. 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 1622884655 387 VTYMSQVLIQCAGSEEKNERYLLLFPNVLLMLSASPRMSGFIYQGKLPTTGMTITKLEDSENHRNAFEISgdrhklcecr 466
Cdd:cd01225     1 VIHMSQVAVQNTGCQEKKERYFLLFPHVLLMLSASPRMSGFIYEGKLPLTGISVNRLEDTEGIKNAFEIS---------- 70

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*....
gi 1622884655 467 vsgrrgslspradsclhiseGSMIERILVSCNNQQDLQEWVDHLQKQTK 515
Cdd:cd01225    71 --------------------GPLIERIVVICNSQQDQQEWLEHLQQQTK 99

betaPIX coiled coil; betaPIX_CC is the very C-terminal coiled-coil region of betaPIX or p21-activated kinase interacting exchange factor proteins. The coiled-coil runs from residues 589-646 in UniProtKB:G31IU6, and the PDZ-binding site is the final eight residues immediately downstream. The coiled-coil trimerizes and thus exposes three potential PZD-binding surfaces, although only one of these is maximally used. One of the C-terminal ends of the coiled-coil forms an extensive beta-sheet interaction with the Shank PDZ, while the other two ends are not involved in ligand binding and form random coils. Thus the coiled-coil domain allows multimerization of betaPIX that is vital for its physiological functions. betaPIX and the Shank/ProSAP protein form a complex that acts as a protein scaffold for integrating signalling pathways and regulating postsynaptic structure.** Forced reload

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 735 APQVLLPEEEKIIVEETKSNgQTVIEEKSLVDTVYALKDEVQELRQDNKKMKKSLEEEQRARKDLEKLVRKVLKNMNDPA 814
Cdd:pfam16523   1 QPHVLVPEEEKIIVEETKSN-QTVLQEKSLVDAVYALKDEVQELKQENKKMKKSLEEEQKARRRLEKVVRKLLKSINDPG 79

                  ....*
gi 1622884655 815 WDETN 819
Cdd:pfam16523  80 WDETN 84

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 1622884655  182 VLQNILETENEYSKELQTVLSTYLRPLQTSEKLSSAN-ISYLMGNLEEICSFQQMLVQSLEECTKLPE-AQQRVGGCFLN 259
Cdd:smart00325   1 VLKELLQTERNYVRDLKLLVEVFLKPLKKELKLLSPNeLETLFGNIEEIYEFHRDFLDELEERIEEWDdSVERIGDVFLK 80

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655  260 LMPqMKTLYLTYCANHPSAVNVLTE--HSEELGEFMETKGASSPGI-LVLTTGLSKPFMRLDKYPTLLKELERHMEDYHT 336
Cdd:smart00325  81 LEE-FFKIYSEYCSNHPDALELLKKlkKNPRFQKFLKEIESSPQCRrLTLESLLLKPVQRLTKYPLLLKELLKHTPEDHE 159

                          170       180
                   ....*....|....*....|.
gi 1622884655  337 DRQDIQKSMAAFKNLSAQCQE 357
Cdd:smart00325 160 DREDLKKALKAIKELANQVNE 180

RhoGEF domain; Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases Also called Dbl-homologous (DH) domain. It appears that pfam00169 domains invariably occur C-terminal to RhoGEF/DH domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 182 VLQNILETENEYSKELQTVLSTYLRPLQTSEKLSSANISYLMGNLEEICSFQQMLVqsLEECTKLPEAQQRVGGCFLNLM 261
Cdd:pfam00621   1 VIKELLQTERSYVRDLEILVEVFLPPNSKPLSESEEEIKTIFSNIEEIYELHRQLL--LEELLKEWISIQRIGDIFLKFA 78

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 262 PQMKtLYLTYCANHPSAVNVLTEHSEELGEFM----ETKGASSPGILVLTTGLSKPFMRLDKYPTLLKELERHMEDYHTD 337
Cdd:pfam00621  79 PGFK-VYSTYCSNYPKALKLLKKLLKKNPKFRafleELEANPECRGLDLNSFLIKPVQRIPRYPLLLKELLKHTPPDHPD 157

                         170
                  ....*....|....*...
gi 1622884655 338 RQDIQKSMAAFKNLSAQC 355
Cdd:pfam00621 158 YEDLKKALEAIKEVAKQI 175

Variant 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        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1622884655  95 VVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVREV 148
Cdd:pfam07653   1 YGRVIFDYVGTDKNGLTLKKGDVVKVLGKDNDGWWEGETGGRVGLVPSTAVEEI 54

Calponin homology (CH) domain; The CH domain is found in both cytoskeletal proteins and signal transduction proteins. The CH domain is involved in actin binding in some members of the family. However in calponins there is evidence that the CH domain is not involved in its actin binding activity. Most member proteins have from two to four copies of the CH domain, however some proteins such as calponin have only a single copy.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655   5 EQTVTWLITLGVLESPKKTISDpegfLQASLKDGVVLCRLLERLLPGTIEKVyPEPRSESECLSNIREFLRGCGASLRL- 83
Cdd:pfam00307   5 KELLRWINSHLAEYGPGVRVTN----FTTDLRDGLALCALLNKLAPGLVDKK-KLNKSEFDKLENINLALDVAEKKLGVp 79

                          90       100
                  ....*....|....*....|
gi 1622884655  84 ------EDMTDNsNNQLVVR 97
Cdd:pfam00307  80 kvliepEDLVEG-DNKSVLT 98

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 1622884655  399 GSEEKNERYLLLFPNVLLMLSASPRMSGFIYQGKLPTTGMTITKLEDSEN--HRNAFEISGDRHKlcecrvsgrrgslsp 476
Cdd:smart00233  14 GKKSWKKRYFVLFNSTLLYYKSKKDKKSYKPKGSIDLSGCTVREAPDPDSskKPHCFEIKTSDRK--------------- 78

                           90       100       110
                   ....*....|....*....|....*....|....*....
gi 1622884655  477 radsclhisegsmieRILVSCNNQQDLQEWVDHLQKQTK 515
Cdd:smart00233  79 ---------------TLLLQAESEEEREKWVEALRKAIA 102

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655  189 TENEYSKELQTVLSTYLRPLQTSEKLSSAN----ISYLMGNLEEICSFQQMLVQSLEECTKLPEAQQRVGGCFLNLMPQM 264
Cdd:COG5422    495 TERDFVKDLEYLRDTWIKPLEESNIIPENArrnfIKHVFANINEIYAVNSKLLKALTNRQCLSPIVNGIADIFLDYVPKF 574

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655  265 KTlYLTYCANHPSAVNVLTEHSEELGEFM----ETKGASSPGILVLTTGLSKPFMRLDKYPTLLKELERHMEDYHTDRQD 340
Cdd:COG5422    575 EP-FIKYGASQPYAKYEFEREKSVNPNFArfdhEVERLDESRKLELDGYLTKPTTRLARYPLLLEEVLKFTDPDNPDTED 653

                          170
                   ....*....|..
gi 1622884655  341 IQKSMAAFKNLS 352
Cdd:COG5422    654 IPKVIDMLREFL 665

Cloned out of library/PAK-interactive exchange factor pleckstrin homology (PH) domain; There are two forms of Pix proteins: alpha Pix (also called Rho guanine nucleotide exchange factor (GEF) 6/90Cool-2) and beta Pix (GEF7/p85Cool-1). betaPix contains an N-terminal SH3 domain, a RhoGEF/DH domain, a PH domain, a GIT1 binding domain (GBD), and a C-terminal coiled-coil (CC) domain. alphaPix differs in that it contains a calponin homology (CH) domain, which interacts with beta-parvin, N-terminal to the SH3 domain. alphaPix is an exchange factor for Rac1 and Cdc42 and mediates Pak activation on cell adhesion to fibronectin. Mutations in alphaPix can cause X-linked mental retardation. alphaPix also interacts with Huntington's disease protein (htt), and enhances the aggregation of mutant htt (muthtt) by facilitating SDS-soluble muthtt-muthtt interactions. The DH-PH domain of a Pix was required for its binding to htt. In the majority of Rho GEF proteins, the DH-PH domain is responsible for the exchange activity. 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 1622884655 387 VTYMSQVLIQCAGSEEKNERYLLLFPNVLLMLSASPRMSGFIYQGKLPTTGMTITKLEDSENHRNAFEISgdrhklcecr 466
Cdd:cd01225     1 VIHMSQVAVQNTGCQEKKERYFLLFPHVLLMLSASPRMSGFIYEGKLPLTGISVNRLEDTEGIKNAFEIS---------- 70

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*....
gi 1622884655 467 vsgrrgslspradsclhiseGSMIERILVSCNNQQDLQEWVDHLQKQTK 515
Cdd:cd01225    71 --------------------GPLIERIVVICNSQQDQQEWLEHLQQQTK 99

betaPIX coiled coil; betaPIX_CC is the very C-terminal coiled-coil region of betaPIX or p21-activated kinase interacting exchange factor proteins. The coiled-coil runs from residues 589-646 in UniProtKB:G31IU6, and the PDZ-binding site is the final eight residues immediately downstream. The coiled-coil trimerizes and thus exposes three potential PZD-binding surfaces, although only one of these is maximally used. One of the C-terminal ends of the coiled-coil forms an extensive beta-sheet interaction with the Shank PDZ, while the other two ends are not involved in ligand binding and form random coils. Thus the coiled-coil domain allows multimerization of betaPIX that is vital for its physiological functions. betaPIX and the Shank/ProSAP protein form a complex that acts as a protein scaffold for integrating signalling pathways and regulating postsynaptic structure.** Forced reload

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 735 APQVLLPEEEKIIVEETKSNgQTVIEEKSLVDTVYALKDEVQELRQDNKKMKKSLEEEQRARKDLEKLVRKVLKNMNDPA 814
Cdd:pfam16523   1 QPHVLVPEEEKIIVEETKSN-QTVLQEKSLVDAVYALKDEVQELKQENKKMKKSLEEEQKARRRLEKVVRKLLKSINDPG 79

                  ....*
gi 1622884655 815 WDETN 819
Cdd:pfam16523  80 WDETN 84

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 1622884655 179 YNVVLQNILETENEYSKELQTVLSTYLRPLQTSEK-LSSANISYLMGNLEEICSFQQMLVQSLEECTKL-PEAQQRVGGC 256
Cdd:cd00160     1 RQEVIKELLQTERNYVRDLKLLVEVFLKPLDKELLpLSPEEVELLFGNIEEIYEFHRIFLKSLEERVEEwDKSGPRIGDV 80

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 257 FLNLMPQMKTlYLTYCANHPSAVNVLTEHSEELGEFME--TKGASSPGILVLTTGLSKPFMRLDKYPTLLKELERHMEDY 334
Cdd:cd00160    81 FLKLAPFFKI-YSEYCSNHPDALELLKKLKKFNKFFQEflEKAESECGRLKLESLLLKPVQRLTKYPLLLKELLKHTPDG 159

                         170       180
                  ....*....|....*....|..
gi 1622884655 335 HTDRQDIQKSMAAFKNLSAQCQ 356
Cdd:cd00160   160 HEDREDLKKALEAIKEVASQVN 181

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 1622884655  182 VLQNILETENEYSKELQTVLSTYLRPLQTSEKLSSAN-ISYLMGNLEEICSFQQMLVQSLEECTKLPE-AQQRVGGCFLN 259
Cdd:smart00325   1 VLKELLQTERNYVRDLKLLVEVFLKPLKKELKLLSPNeLETLFGNIEEIYEFHRDFLDELEERIEEWDdSVERIGDVFLK 80

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655  260 LMPqMKTLYLTYCANHPSAVNVLTE--HSEELGEFMETKGASSPGI-LVLTTGLSKPFMRLDKYPTLLKELERHMEDYHT 336
Cdd:smart00325  81 LEE-FFKIYSEYCSNHPDALELLKKlkKNPRFQKFLKEIESSPQCRrLTLESLLLKPVQRLTKYPLLLKELLKHTPEDHE 159

                          170       180
                   ....*....|....*....|.
gi 1622884655  337 DRQDIQKSMAAFKNLSAQCQE 357
Cdd:smart00325 160 DREDLKKALKAIKELANQVNE 180

Src Homology 3 domain of alpha-Pak Interactive eXchange factor; Alpha-PIX, also called Rho guanine nucleotide exchange factor 6 (ARHGEF6) or Cool (Cloned out of Library)-2, activates small GTPases by exchanging bound GDP for free GTP. It acts as a GEF for both Cdc42 and Rac 1, and is localized in dendritic spines where it regulates spine morphogenesis. It controls dendritic length and spine density in the hippocampus. Mutations in the ARHGEF6 gene cause X-linked intellectual disability in humans. 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 1622884655  93 QLVVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVREVKA 150
Cdd:cd12060     1 QLVVKARFNFKQTNEDELSVCKGDIIYVTRVEEGGWWEGTLNGKTGWFPSNYVREIKS 58

RhoGEF domain; Guanine nucleotide exchange factor for Rho/Rac/Cdc42-like GTPases Also called Dbl-homologous (DH) domain. It appears that pfam00169 domains invariably occur C-terminal to RhoGEF/DH domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 182 VLQNILETENEYSKELQTVLSTYLRPLQTSEKLSSANISYLMGNLEEICSFQQMLVqsLEECTKLPEAQQRVGGCFLNLM 261
Cdd:pfam00621   1 VIKELLQTERSYVRDLEILVEVFLPPNSKPLSESEEEIKTIFSNIEEIYELHRQLL--LEELLKEWISIQRIGDIFLKFA 78

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655 262 PQMKtLYLTYCANHPSAVNVLTEHSEELGEFM----ETKGASSPGILVLTTGLSKPFMRLDKYPTLLKELERHMEDYHTD 337
Cdd:pfam00621  79 PGFK-VYSTYCSNYPKALKLLKKLLKKNPKFRafleELEANPECRGLDLNSFLIKPVQRIPRYPLLLKELLKHTPPDHPD 157

                         170
                  ....*....|....*...
gi 1622884655 338 RQDIQKSMAAFKNLSAQC 355
Cdd:pfam00621 158 YEDLKKALEAIKEVAKQI 175

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1622884655  95 VVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLN-GRTGWFPSNY 144
Cdd:cd00174     1 YARALYDYEAQDDDELSFKKGDIITVLEKDDDGWWEGELNgGREGLFPANY 51

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1622884655  95 VVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd11766     1 PAVVKFNYEAQREDELSLRKGDRVLVLEKSSDGWWRGECNGQVGWFPSNYVTE 53

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        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1622884655  96 VRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd11873     2 VIVEFDYDAEEPDELTLKVGDIITNVKKMEEGWWEGTLNGKRGMFPDNFVKV 53

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        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1622884655  97 RAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd11874     3 KVLFSYTPQNEDELELKVGDTIEVLGEVEEGWWEGKLNGKVGVFPSNFVKE 53

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        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1622884655  97 RAKFNFQQTNEDELSFSKGDVIHVTR--VEEGGWWEGTLNGRTGWFPSNYV 145
Cdd:cd12142     3 RVLFDYNPVAPDELALKKGDVIEVISkeTEDEGWWEGELNGRRGFFPDNFV 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 1622884655  97 RAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd11823     3 KALYSYTANREDELSLQPGDIIEVHEKQDDGWWLGELNGKKGIFPATYVEE 53

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

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1622884655  97 RAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLN-GRTGWFPS 142
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVLEKSEDGWWKGRNKgGKEGLIPS 47

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 1622884655  97 RAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd12055     3 QVAFSYLPQNEDELELKVGDIIEVVGEVEEGWWEGVLNGKTGMFPSNFIKE 53

C-terminal (or second) Src homology 3 domain of VAV proteins; VAV proteins function both as cytoplasmic guanine nucleotide exchange factors (GEFs) for Rho GTPases and scaffold proteins and they play important roles in cell signaling by coupling cell surface receptors to various effector functions. They play key roles in processes that require cytoskeletal reorganization including immune synapse formation, phagocytosis, cell spreading, and platelet aggregation, among others. Vertebrates have three VAV proteins (VAV1, VAV2, and VAV3). VAV proteins contain several domains that enable their function: N-terminal calponin homology (CH), acidic, RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), C1 (zinc finger), SH2, and two SH3 domains. The SH3 domain of VAV is involved in the localization of proteins to specific sites within the cell, by interacting with proline-rich sequences within target 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 1622884655  98 AKFNFQQTNEDELSFSKGDVIHV-TRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd11830     4 ARYDFCARDMRELSLKEGDVVKIyNKKGQQGWWRGEINGRIGWFPSTYVEE 54

Fifth Src homology 3 domain (or SH3E) 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 fifth SH3 domain (or SH3E) of ITSN2 is expected to bind protein partners, similar to ITSN1 which 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 1622884655  96 VRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVR 146
Cdd:cd11996     3 VIAMYDYTANNEDELSFSKGQLINVLNKDDPDWWQGEINGVTGLFPSNYVK 53

Second Src Homology 3 domain of Nck1 adaptor protein; Nck1 (also called Nckalpha) plays a crucial role in connecting signaling pathways of tyrosine kinase receptors and important effectors in actin dynamics and cytoskeletal remodeling. It binds and activates RasGAP, resulting in the downregulation of Ras. It is also involved in the signaling of endothilin-mediated inhibition of cell migration. 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, which show partly overlapping functions but also bind distinct targets. 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 1622884655  99 KFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd11901     7 KFNYTAEREDELSLVKGTKVIVMEKCSDGWWRGSYNGQVGWFPSNYVTE 55

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1622884655  95 VVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYV 145
Cdd:cd11781     1 KARALYPFKAQSAKELSLKKGDIIYIRRQIDKNWYEGEHNGRVGIFPASYV 51

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
                  ....*....|....*....|....*....|....*....|....*....
gi 1622884655 100 FNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVREV 148
Cdd:cd12054     7 FEYVPQNEDELELKVGDIIDINEEVEEGWWSGTLNGKSGLFPSNFVKEL 55

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1622884655  96 VRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVR 146
Cdd:cd11949     2 VQALFDFDPQEDGELGFRRGDFIEVMDNSDPNWWKGACHGQTGMFPRNYVT 52

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 1622884655  95 VVRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRT-----GWFPSNY 144
Cdd:cd11883     1 VVVALYDFTPKSKNQLSFKAGDIIYVLNKDPSGWWDGVIISSSgkvkrGWFPSNY 55

calponin homology (CH) domain superfamily; CH domains are actin filament (F-actin) binding motifs, which may be present as a single copy or in tandem repeats (which increase binding affinity). They either function as autonomous actin binding motifs or serve a regulatory function. CH domains are found in cytoskeletal and signal transduction proteins, including actin-binding proteins like spectrin, alpha-actinin, dystrophin, utrophin, and fimbrin, as well as proteins essential for regulation of cell shape (cortexillins), and signaling proteins (Vav).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1622884655  21 KKTISDPEGFLQASLKDGVVLCRLLERLLPGTIEKVYPEPRSESECLSNIREFLRGCGA-------SLRLEDMTDNSNNQ 93
Cdd:cd00014    13 GEELPVSITDLFESLRDGVLLCKLINKLSPGSIPKINKKPKSPFKKRENINLFLNACKKlglpeldLFEPEDLYEKGNLK 92

                  ....
gi 1622884655  94 LVVR 97
Cdd:cd00014    93 KVLG 96

Src homology 3 domain of Phospholipase C (PLC) gamma; PLC catalyzes the hydrolysis of phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] to produce Ins(1,4,5)P3 and diacylglycerol (DAG) in response to various receptors. Ins(1,4,5)P3 initiates the calcium signaling cascade while DAG functions as an activator of PKC. PLCgamma catalyzes this reaction in tyrosine kinase-dependent signaling pathways. It is activated and recruited to its substrate at the membrane. Vertebrates contain two forms of PLCgamma, PLCgamma1, which is widely expressed, and PLCgamma2, which is primarily found in haematopoietic cells. 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.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1622884655  96 VRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGR-TGWFPSNYVRE 147
Cdd:cd11825     2 VKALYDYRAQRPDELSFCKHAIITNVEKEDGGWWRGDYGGKkQKWFPANYVEE 54

C-terminal (or second) Src homology 3 domain of VAV1 protein; VAV1 is expressed predominantly in the hematopoietic system and it plays an important role in the development and activation of B and T cells. It is activated by tyrosine phosphorylation to function as a guanine nucleotide exchange factor (GEF) for Rho GTPases following cell surface receptor activation, triggering various effects such as cytoskeletal reorganization, transcription regulation, cell cycle progression, and calcium mobilization. It also serves as a scaffold protein and has been shown to interact with Ku70, Socs1, Janus kinase 2, SIAH2, S100B, Abl gene, ZAP-70, SLP76, and Syk, among others. VAV proteins contain several domains that enable their function: N-terminal calponin homology (CH), acidic, RhoGEF (also called Dbl-homologous or DH), Pleckstrin Homology (PH), C1 (zinc finger), SH2, and two SH3 domains. The C-terminal SH3 domain of Vav1 interacts with a wide variety of proteins including cytoskeletal regulators (zyxin), RNA-binding proteins (Sam68), transcriptional regulators, viral proteins, and dynamin 2. 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 1622884655  95 VVRAKFNFQQTNEDELSFSKGDVIHV-TRVEEGGWWEGTLNGRTGWFPSNYVRE 147
Cdd:cd11976     1 TAKARYDFCARDRSELSLKEGDIIKIlNKKGQQGWWRGEIYGRVGWFPANYVEE 54

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.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1622884655  96 VRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTG-WFPSNYVREV 148
Cdd:cd11970     6 VKALFDYKAQREDELTFTKNAIIQNVEKQEGGWWRGDYGGKKQlWFPSNYVEEI 59

Fifth Src homology 3 domain (or SH3E) of Intersectin-1; Intersectin-1 (ITSN1) is an adaptor protein that functions in exo- and endocytosis, actin cytoskeletal reorganization, and signal transduction. It plays a role in clathrin-coated pit (CCP) formation. It binds to many proteins through its multidomain structure and facilitate the assembly of multimeric complexes. ITSN1 localizes in membranous organelles, CCPs, the Golgi complex, and may be involved in the cell membrane trafficking system. It exists in alternatively spliced short and long isoforms. The short isoform contains two Eps15 homology domains (EH1 and EH2), a coiled-coil region and five SH3 domains (SH3A-E), while the long isoform, in addition, contains RhoGEF (also called Dbl-homologous or DH), Pleckstrin homology (PH) and C2 domains. The 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
                  ....*....|....*....|....*....|....*....|....*..
gi 1622884655 100 FNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVR 146
Cdd:cd11995     7 YDYTAQNDDELAFSKGQIINVLNKEDPDWWKGELNGQVGLFPSNYVK 53

C-terminal Src homology 3 domain of GRB2-related adaptor protein 2; GRAP2 is also called GADS (GRB2-related adapter downstream of Shc), GrpL, GRB2L, Mona, or GRID (Grb2-related protein with insert domain). It is expressed specifically in the hematopoietic system. It plays an important role in T cell receptor (TCR) signaling by promoting the formation of the SLP-76:LAT complex, which couples the TCR to the Ras pathway. It also has roles in antigen-receptor and tyrosine kinase mediated signaling. GRAP2 is unique from other GRB2-like adaptor proteins in that it can be regulated by caspase cleavage. It contains an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. The C-terminal SH3 domain of GRAP2 binds to different motifs found in substrate peptides including the typical PxxP motif in hematopoietic progenitor kinase 1 (HPK1), the RxxK motif in SLP-76 and HPK1, and the RxxxxK motif in phosphatase-like protein HD-PTP. SH3 domains are protein interaction domains that typically bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1622884655  96 VRAKFNFQQTNEDELSFSKGDVIHVTRVEEGGWWEGTLNGRTGWFPSNYVR 146
Cdd:cd11950     2 VRALYDFEALEDDELGFNSGDVIEVLDSSNPSWWKGRLHGKLGLFPANYVA 52