The phosphoinositide binding Phox Homology domain of Sorting Nexin 18; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. SNX18, like SNX9, contains an N-terminal Src Homology 3 (SH3) domain, a PX domain, and a C-terminal Bin/Amphiphysin/Rvs (BAR) domain, which detects membrane curvature. The PX-BAR structural unit helps determine specific membrane localization. SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 276 FQCTIDDPTKQTKFKGMKSYISYKLVPTHTQVPVHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEEDFISKRRKG 355
Cdd:cd07286     1 FQCTIDDPTKQTKFKGMKSYISYKLVPSHTGLQVHRRYKHFDWLYARLAEKFPVISVPHIPEKQATGRFEEDFISKRRKG 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*...
gi 1034643448 356 LIWWMNHMASHPVLAQCDVFQHFLTCPsSTDEKAWKQGKRKAEKDEMV 403
Cdd:cd07286    81 LIWWMDHMCSHPVLARCDAFQHFLTCP-STDEKAWKQGKRKAEKDEMV 127

Src Homology 3 domain of Sorting nexin 18; SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1. It binds FIP5 and is required for apical lumen formation. It may also play a role in axonal elongation. SNXs are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNX18 also contains BAR 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 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQDIEGWLEGVNSRGDRGLFPASYVQV 58
Cdd:cd11897     1 RARALYDFRSENPGEISLREHEVLSLCSEQDIEGWLEGVNSRGDRGLFPASYVEV 55

The phosphoinositide binding Phox Homology domain of Sorting Nexin 18; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. SNX18, like SNX9, contains an N-terminal Src Homology 3 (SH3) domain, a PX domain, and a C-terminal Bin/Amphiphysin/Rvs (BAR) domain, which detects membrane curvature. The PX-BAR structural unit helps determine specific membrane localization. SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 276 FQCTIDDPTKQTKFKGMKSYISYKLVPTHTQVPVHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEEDFISKRRKG 355
Cdd:cd07286     1 FQCTIDDPTKQTKFKGMKSYISYKLVPSHTGLQVHRRYKHFDWLYARLAEKFPVISVPHIPEKQATGRFEEDFISKRRKG 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*...
gi 1034643448 356 LIWWMNHMASHPVLAQCDVFQHFLTCPsSTDEKAWKQGKRKAEKDEMV 403
Cdd:cd07286    81 LIWWMDHMCSHPVLARCDAFQHFLTCP-STDEKAWKQGKRKAEKDEMV 127

WASP-binding domain of Sorting nexin protein; The C-terminal region of the Sorting nexin group of proteins appears to carry a BAR-like (Bin/amphiphysin/Rvs) domain. This domain is very diverse and the similarities with other BAR domains are few. In the Sorting nexins it is associated with family PX, pfam00787.13, and in combination with PX appears to be necessary to bind WASP along with p85 to form a multimeric signalling complex.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 386 DEKAWKQGKRKAEKDEMVGANFFLTLsTPPAAALDLQEVESKIDGFKCFTKKMDDSALQLNHTANEFARKQVTGFKKEYQ 465
Cdd:pfam10456   1 DEKEWKTGKRKAEKDELVGAMFFLTI-EIPEPPLDLQEVEQKVEGFKRFTKKMDDSVKQLLTVGNEFWKKCTGPFKKEYQ 79

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1034643448 466 KVGQSFRGLSQAFELDQQAFSVGLNQAIAFTGDAYDAIGELFAEQPRQDLDPVMDLLALYQGHLANFPDIIHVQKG 541
Cdd:pfam10456  80 KIGSAFQLLSQVFEMDGYVGSSALNEAIAHTGKTYEEIGEVFAEQPKKDLHPLLETLSEYKGLLGNFPDIIHVHKG 155

PX domain; PX domains bind to phosphoinositides.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1034643448 309 VHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEEDFISKRRKGLIWWMNHMASHPVLAQCDVFQHFLTCP 382
Cdd:pfam00787  11 VRRRYSDFVELHKKLLRKFPSVIIPPLPPKRWLGRYNEEFIEKRRKGLEQYLQRLLQHPELRNSEVLLEFLESD 84

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 1034643448    4 RARALYDFRSENPGEISLREHEVLSLCSEQDiEGWLEGVNSRGDRGLFPASYVQ 57
Cdd:smart00326   4 QVRALYDYTAQDPDELSFKKGDIITVLEKSD-DGWWKGRLGRGKEGLFPSNYVE 56

Variant SH3 domain;

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|.
gi 1034643448   7 ALYDFRSENPGEISLREHEVLSLcSEQDIEGWLEGVNsRGDRGLFPASYVQ 57
Cdd:pfam14604   1 ALYPYEPKDDDELSLQRGDVITV-IEESEDGWWEGIN-TGRTGLVPANYVE 49

The phosphoinositide binding Phox Homology domain of Sorting Nexin 18; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. SNX18, like SNX9, contains an N-terminal Src Homology 3 (SH3) domain, a PX domain, and a C-terminal Bin/Amphiphysin/Rvs (BAR) domain, which detects membrane curvature. The PX-BAR structural unit helps determine specific membrane localization. SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 276 FQCTIDDPTKQTKFKGMKSYISYKLVPTHTQVPVHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEEDFISKRRKG 355
Cdd:cd07286     1 FQCTIDDPTKQTKFKGMKSYISYKLVPSHTGLQVHRRYKHFDWLYARLAEKFPVISVPHIPEKQATGRFEEDFISKRRKG 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*...
gi 1034643448 356 LIWWMNHMASHPVLAQCDVFQHFLTCPsSTDEKAWKQGKRKAEKDEMV 403
Cdd:cd07286    81 LIWWMDHMCSHPVLARCDAFQHFLTCP-STDEKAWKQGKRKAEKDEMV 127

WASP-binding domain of Sorting nexin protein; The C-terminal region of the Sorting nexin group of proteins appears to carry a BAR-like (Bin/amphiphysin/Rvs) domain. This domain is very diverse and the similarities with other BAR domains are few. In the Sorting nexins it is associated with family PX, pfam00787.13, and in combination with PX appears to be necessary to bind WASP along with p85 to form a multimeric signalling complex.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 386 DEKAWKQGKRKAEKDEMVGANFFLTLsTPPAAALDLQEVESKIDGFKCFTKKMDDSALQLNHTANEFARKQVTGFKKEYQ 465
Cdd:pfam10456   1 DEKEWKTGKRKAEKDELVGAMFFLTI-EIPEPPLDLQEVEQKVEGFKRFTKKMDDSVKQLLTVGNEFWKKCTGPFKKEYQ 79

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1034643448 466 KVGQSFRGLSQAFELDQQAFSVGLNQAIAFTGDAYDAIGELFAEQPRQDLDPVMDLLALYQGHLANFPDIIHVQKG 541
Cdd:pfam10456  80 KIGSAFQLLSQVFEMDGYVGSSALNEAIAHTGKTYEEIGEVFAEQPKKDLHPLLETLSEYKGLLGNFPDIIHVHKG 155

The Bin/Amphiphysin/Rvs (BAR) domain of Sorting Nexin 9 and Similar Proteins; BAR domains are dimerization, lipid binding and curvature sensing modules found in many different proteins with diverse functions. Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. A subset of SNXs also contain BAR domains. The PX-BAR structural unit determines the specific membrane targeting of SNXs. This subfamily consists of SNX9, SNX18, SNX33, and similar proteins. SNX9 is localized to plasma membrane endocytic sites and acts primarily in clathrin-mediated endocytosis, while SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1. BAR domains form dimers that bind to membranes, induce membrane bending and curvature, and may also be involved in protein-protein interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 423 EVESKIDGFKCFTKKMDDSALQLNHTANEFARKQVTGFKKEYQKVGQSFRGLSQAFELDQQAFSVGLNQAIAFTGDAYDA 502
Cdd:cd07626     1 DVEQQVDAFKKFVKSMDDSVKNLINIAQEQAKKHQGPYKKEYQKIGQAFTSLGTAFELDETPTSVPLTQAIKHTGQAYEE 80

                          90       100       110
                  ....*....|....*....|....*....|....*....
gi 1034643448 503 IGELFAEQPRQDLDPVMDLLALYQGHLANFPDIIHVQKG 541
Cdd:cd07626    81 IGELFAEQPKHDLIPLLDGLHEYKGLLSTFPDIIGVHKG 119

The Bin/Amphiphysin/Rvs (BAR) domain of Sorting Nexin 33; BAR domains are dimerization, lipid binding and curvature sensing modules found in many different proteins with diverse functions. Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. A subset of SNXs also contain BAR domains. The PX-BAR structural unit determines the specific membrane targeting of SNXs. SNX33 interacts with Wiskott-Aldrich syndrome protein (WASP) and plays a role in the maintenance of cell shape and cell cycle progression. It modulates the shedding and endocytosis of cellular prion protein (PrP(c)) and amyloid precursor protein (APP). BAR domains form dimers that bind to membranes, induce membrane bending and curvature, and may also be involved in protein-protein interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 415 PAAALDLQEVESKIDGFKCFTKKMDDSALQLNHTANEFARKQVTGFKKEYQKVGQSFRGLSQAFELDQQAFSVGLNQAIA 494
Cdd:cd07669     1 PTEHQDLQDVEERVDVFKAFSKKMDDSVLQLSNVASELVRKHLGGFRKEFQKLGNAFQAISHSFQLDPPYSSEALNNAIS 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*..
gi 1034643448 495 FTGDAYDAIGELFAEQPRQDLDPVMDLLALYQGHLANFPDIIHVQKG 541
Cdd:cd07669    81 HTGRTYEAVGEMFAEQPKNDLFQMLDTLSLYQGLLSNFPDIIHLQKG 127

The phosphoinositide binding Phox Homology domain of Sorting Nexins 1 and 2; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. This subfamily consists of SNX1, SNX2, and similar proteins. They harbor a Bin/Amphiphysin/Rvs (BAR) domain, which detects membrane curvature, C-terminal to the PX domain. Both domains have been shown to determine the specific membrane-targeting of SNX1. SNX1 and SNX2 are components of the retromer complex, a membrane coat multimeric complex required for endosomal retrieval of lysosomal hydrolase receptors to the Golgi. The retromer consists of a cargo-recognition subcomplex and a subcomplex formed by a dimer of sorting nexins (SNX1 and/or SNX2), which ensures effcient cargo sorting by facilitating proper membrane localization of the cargo-recognition subcomplex.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 276 FQCTIDDPTKQTKfkGMKSYISYKlVPTHTQVP--------VHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEE- 346
Cdd:cd06859     1 FEISVTDPVKVGD--GMSAYVVYR-VTTKTNLPdfkksefsVLRRYSDFLWLYERLVEKYPGRIVPPPPEKQAVGRFKVk 77

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1034643448 347 -DFISKRRKGLIWWMNHMASHPVLAQCDVFQHFLT 380
Cdd:cd06859    78 fEFIEKRRAALERFLRRIAAHPVLRKDPDFRLFLE 112

The Phox Homology domain, a phosphoinositide binding module; The PX domain is a phosphoinositide (PI) binding module involved in targeting proteins to membranes. Proteins containing PX domains interact with PIs and have been implicated in highly diverse functions such as cell signaling, vesicular trafficking, protein sorting, lipid modification, cell polarity and division, activation of T and B cells, and cell survival. Many members of this superfamily bind phosphatidylinositol-3-phosphate (PI3P) but in some cases, other PIs such as PI4P or PI(3,4)P2, among others, are the preferred substrates. In addition to protein-lipid interaction, the PX domain may also be involved in protein-protein interaction, as in the cases of p40phox, p47phox, and some sorting nexins (SNXs). The PX domain is conserved from yeast to humans and is found in more than 100 proteins. The majority of PX domain-containing proteins are SNXs, which play important roles in endosomal sorting.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 277 QCTIDDPtkQTKFKGMKSYISYKLVPTHTQVP---VHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEEDFISKRR 353
Cdd:cd06093     1 SVSIPDY--EKVKDGGKKYVVYIIEVTTQGGEewtVYRRYSDFEELHEKLKKKFPGVILPPLPPKKLFGNLDPEFIEERR 78

                          90       100
                  ....*....|....*....|....*..
gi 1034643448 354 KGLIWWMNHMASHPVLAQCDVFQHFLT 380
Cdd:cd06093    79 KQLEQYLQSLLNHPELRNSEELKEFLE 105

The Bin/Amphiphysin/Rvs (BAR) domain of Sorting Nexin 9; BAR domains are dimerization, lipid binding and curvature sensing modules found in many different proteins with diverse functions. Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. A subset of SNXs also contain BAR domains. The PX-BAR structural unit determines the specific membrane targeting of SNXs. SNX9, also known as SH3PX1, is a cytosolic protein that interacts with proteins associated with clathrin-coated pits such as Cdc-42-associated tyrosine kinase 2 (ACK2). It binds class I polyproline sequences found in dynamin 1/2 and the WASP/N-WASP actin regulators. SNX9 is localized to plasma membrane endocytic sites and acts primarily in clathrin-mediated endocytosis. Its array of interacting partners suggests that SNX9 functions at the interface between endocytosis and actin cytoskeletal organization. BAR domains form dimers that bind to membranes, induce membrane bending and curvature, and may also be involved in protein-protein interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 416 AAALDLQEVESKIDGFKCFTKKMDDSALQLNHTANEFARKQVTGFKKEYQKVGQSFRGLSQAFELDQQAFSVGLNQAIAF 495
Cdd:cd07668     2 APDLDLVEIEQKCEAVGRFTKAMDDGVKELLTVGQEHWKRCTGPLPKEYQKIGKALQSLATVFSTSGYQGETDLNDAITE 81

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*.
gi 1034643448 496 TGDAYDAIGELFAEQPRQDLDPVMDLLALYQGHLANFPDIIHVQKG 541
Cdd:cd07668    82 AGKTYEEIASLVAEQPKKDLHFLMETNHEYKGFLGCFPDIIGAHKG 127

The phosphoinositide binding Phox Homology domain of Sorting Nexins 7 and 30; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. Some SNXs are localized in early endosome structures such as clathrin-coated pits, while others are located in late structures of the endocytic pathway. This subfamily consists of SNX7, SNX30, and similar proteins. They harbor a Bin/Amphiphysin/Rvs (BAR) domain, which detects membrane curvature, C-terminal to the PX domain, similar to the sorting nexins SNX1-2, SNX4-6, SNX8, and SNX32. Both domains have been shown to determine the specific membrane-targeting of SNX1. The specific function of the sorting nexins in this subfamily has yet to be elucidated.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 277 QCTIDDPTKQtkFKGMKSYISYKLV--PTHTQVP-----VHRRYKHFDWLYARLAEKFPVISVPHLPEKQAT----GRFE 345
Cdd:cd06860     2 FITVDNPEKH--VTTLETYITYRVTtkTTRSEFDsseysVRRRYQDFLWLRQKLEESHPTHIIPPLPEKHSVkgllDRFS 79

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1034643448 346 EDFISKRRKGLIWWMNHMASHPVLAQCDVFQHFLT 380
Cdd:cd06860    80 PEFVATRMRALHKFLNRIVEHPVLSFNEHLKVFLT 114

PhoX homologous domain, present in p47phox and p40phox; Eukaryotic domain of unknown function present in phox proteins, PLD isoforms, a PI3K isoform.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448  296 ISYKLVPTHTQVpvHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGR---FEEDFISKRRKGLIWWMNHMASHPVLAQ- 371
Cdd:smart00312  19 IETKTGLEEWTV--SRRYSDFLELHSKLKKHFPRSILPPLPGKKLFGRlnnFSEEFIEKRRRGLEKYLQSLLNHPELINh 96

                   ....*....
gi 1034643448  372 CDVFQHFLT 380
Cdd:smart00312  97 SEVVLEFLE 105

The phosphoinositide binding Phox Homology domain of Sorting Nexin 7; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. Some SNXs are localized in early endosome structures such as clathrin-coated pits, while others are located in late structures of the endocytic pathway. SNX7 harbors a Bin/Amphiphysin/Rvs (BAR) domain, which detects membrane curvature, C-terminal to the PX domain, similar to the sorting nexins SNX1-2, SNX4-6, SNX8, SNX30, and SNX32. Both domains have been shown to determine the specific membrane-targeting of SNX1. The specific function of SNX7 has yet to be elucidated.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 279 TIDDPtkQTKFKGMKSYISYKLVPTHT-------QVPVHRRYKHFDWLYARLAEKFPVISVPHLPEK----QATGRFEED 347
Cdd:cd07284     4 TVDEP--ESHVTAIETFITYRVMTKTSrsefdssEFEVRRRYQDFLWLKGRLEEAHPTLIIPPLPEKfvmkGMVERFNED 81

                          90       100       110
                  ....*....|....*....|....*....|...
gi 1034643448 348 FISKRRKGLIWWMNHMASHPVLAQCDVFQHFLT 380
Cdd:cd07284    82 FIETRRKALHKFLNRIADHPTLTFNEDFKIFLT 114

The phosphoinositide binding Phox Homology domain of Sorting Nexin 8 and yeast Mvp1p; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. Some SNXs are localized in early endosome structures such as clathrin-coated pits, while others are located in late structures of the endocytic pathway. SNX8 and the yeast counterpart Mvp1p are involved in sorting and delivery of late-Golgi proteins, such as carboxypeptidase Y, to vacuoles.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1034643448 308 PVHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEEDFISKRRKGLIWWMNHMASHPVLAQCDVFQHFLTCP 382
Cdd:cd06866    31 TVYRRYSDFVWLHEYLLKRYPYRMVPALPPKRIGGSADREFLEARRRGLSRFLNLVARHPVLSEDELVRTFLTEP 105

Phox homology (PX) domain protein [Intracellular trafficking and secretion / General function prediction only];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 273 PYPFQCTIDDPTKQTKFKGMKS-YISYKLVpTHTQVP-----------VHRRYKHFDWLYARLAEKFPVISVPHLPEKQ- 339
Cdd:COG5391   128 DYFISSTVSNPQSLTLLVDSRDkHTSYEII-TVTNLPsfqlresrplvVRRRYSDFESLHSILIKLLPLCAIPPLPSKKs 206

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 340 ----ATGRFEEDFISKRRKGLIWWMNHMASHPVLAQCDVFQHFLTcpSSTDEKAWKQgkrkaekdemvganffLTLSTPP 415
Cdd:COG5391   207 nseyYGDRFSDEFIEERRQSLQNFLRRVSTHPLLSNYKNSKSWES--HSTLLSSFIE----------------NRKSVPT 268

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 416 AAALDLQEVeskidgfkcfTKKMDDSALQLNHTANEFARKQVTGFKKEYQKVGQsFRGLSQAFELDQQAFSVGLNQAIAF 495
Cdd:COG5391   269 PLSLDLTST----------TQELDMERKELNESTSKAIHNILSIFSLFEKILIQ-LESEEESLTRLLESLNNLLLLVLNF 337

                         250       260       270       280
                  ....*....|....*....|....*....|....*....|
gi 1034643448 496 tgdaydaIGELFAEQPRQDLDPVMDLLALYQGHLANFPDI 535
Cdd:COG5391   338 -------SGVFAKRLEQNQNSILNEGVVQAETLRSSLKEL 370

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 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQDiEGWLEGVNSRGDRGLFPASY 55
Cdd:cd00174     1 YARALYDYEAQDDDELSFKKGDIITVLEKDD-DGWWEGELNGGREGLFPANY 51

The phosphoinositide binding Phox Homology domain of SNX-like proteins; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. Some SNXs are localized in early endosome structures such as clathrin-coated pits, while others are located in late structures of the endocytic pathway. This subfamily is composed of uncharacterized proteins, predominantly from plants, with similarity to sorting nexins. A few members show a similar domain architecture as a subfamily of sorting nexins, containing a Bin/Amphiphysin/Rvs (BAR) domain, which detects membrane curvature, C-terminal to the PX domain. The PX-BAR structural unit is known to determine specific membrane localization.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 277 QCTIDDPTKQ----TKFKGMKSYISYKLV-------PTHTQVPVHRRYKHFDWLYARLAEKFPVISVPHLPEK---QATG 342
Cdd:cd06865     1 KITVSDPKKEqepsRVPLGGPPYISYKVTtrtnipsYTHGEFTVRRRFRDVVALADRLAEAYRGAFVPPRPDKsvvESQV 80

                          90       100       110
                  ....*....|....*....|....*....|....*...
gi 1034643448 343 RFEEDFISKRRKGLIWWMNHMASHPVLAQCDVFQHFLT 380
Cdd:cd06865    81 MQSAEFIEQRRVALEKYLNRLAAHPVIGLSDELRVFLT 118

The phosphoinositide binding Phox Homology domain of the fungal protein YPT35; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. This subfamily is composed of YPT35 proteins from the fungal subkingdom Dikarya. The PX domain is involved in targeting of proteins to PI-enriched membranes, and may also be involved in protein-protein interaction. The PX domain of YPT35 binds to phosphatidylinositol 3-phosphate (PI3P). It also serves as a protein interaction domain, binding to members of the Yip1p protein family, which localize to the ER and Golgi. YPT35 is mainly associated with endosomes and together with Yip1p proteins, may be involved in a specific function in the endocytic pathway.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 293 KSYISYKLV-----PTHTQVPVHRRYKHFDWLYARLAEKFP---VISVPHLPEK----QATGRFEEDFISKRRKGLIWWM 360
Cdd:cd07280    20 GAYVVWKITietkdLIGSSIVAYKRYSEFVQLREALLDEFPrhkRNEIPQLPPKvpwyDSRVNLNKAWLEKRRRGLQYFL 99

                          90
                  ....*....|....*....
gi 1034643448 361 NHMASHPVLAQCDVFQHFL 379
Cdd:cd07280   100 NCVLLNPVFGGSPVVKEFL 118

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQDIEGWLEGVNSrGDRGLFPASYVQ 57
Cdd:cd11882     1 RARALYACKAEDESELSFEPGQIITNVQPSDEPGWLEGTLN-GRTGLIPENYVE 53

The phosphoinositide binding Phox Homology domain of fungal Grd19; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. Grd19 is involved in the localization of late Golgi membrane proteins in yeast. Grp19 associates with the retromer complex, a membrane coat multimeric complex required for endosomal retrieval of lysosomal hydrolase receptors to the Golgi, and functions as a cargo-specific adaptor for the retromer.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 280 IDDPTKQTKFKGMKSYISYKLVpTHTQVP--------VHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRFEEDFISK 351
Cdd:cd07295     4 IEVRNPKTHGIGRGMFTDYEIV-CRTNIPafklrvssVRRRYSDFEYFRDILERESPRVMIPPLPGKIFTNRFSDEVIEE 82

                          90
                  ....*....|....*...
gi 1034643448 352 RRKGLIWWMNHMASHPVL 369
Cdd:cd07295    83 RRQGLETFLQSVAGHPLL 100

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQDIEGWLEGVNSRGDRGLFPASYVQ 57
Cdd:cd11999     3 RVRAVYDYTGQEPDELSFKAGEELLKVEDEDEQGWCKGVTDGGAVGLYPANYVE 56

Src Homology 3 domain of Cdc42-Interacting Protein 4; This subfamily is composed of Cdc42-Interacting Protein 4 (CIP4), Formin Binding Protein 17 (FBP17), FormiN Binding Protein 1-Like (FNBP1L), and similar proteins. CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. CIP4 and FBP17 bind to the Fas ligand and may be implicated in the inflammatory response. CIP4 may also play a role in phagocytosis. It functions downstream of Cdc42 in PDGF-dependent actin reorganization and cell migration, and also regulates the activity of PDGFRbeta. It uses Src as a substrate in regulating the invasiveness of breast tumor cells. CIP4 may also play a role in the pathogenesis of Huntington's disease. Members of this subfamily typically contain an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain, a central Cdc42-binding HR1 domain, and a C-terminal SH3 domain. The SH3 domain of CIP4 associates with Gapex-5, a Rab31 GEF. 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 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQDIEGWLEGVNSRGDRGLFPASYVQV 58
Cdd:cd11911     1 TCTALYDFDGTSEGTLSMEEGEILLVLEEDGGDGWTRVRKNNGDEGYVPTSYIEV 55

First Src Homology 3 domain of FCH and double SH3 domains proteins; This group is composed of FCH and double SH3 domains protein 1 (FCHSD1) and FCHSD2. These proteins have a common domain structure consisting of an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), two SH3, and C-terminal proline-rich domains. They have only been characterized in silico and their functions remain unknown. This group also includes the insect protein, nervous wreck, which acts as a regulator of synaptic growth signaling. 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 1034643448   7 ALYDFRSENPGEISLREHEVLSLCSEQDIEGWLEGVNSRGDRGLFPASYVQ 57
Cdd:cd11761     6 VLYSYEAQRPDELTITEGEELEVIEDGDGDGWVKARNKSGEVGYVPENYLQ 56

The phosphoinositide binding Phox Homology domain of fungal Sorting Nexins 41 and 42; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. Some SNXs are localized in early endosome structures such as clathrin-coated pits, while others are located in late structures of the endocytic pathway. SNX41 and SNX42 (also called Atg20p) form dimers with SNX4, and are required in protein recycling from the sorting endosome (post-Golgi endosome) back to the late Golgi in yeast.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 284 TKQTKFKGMKSYISYKL-VPTHTqvpVHRRYKHFDWLYARLAEKFPVISVPHLPEKQATGRF---------EEDFISKRR 353
Cdd:cd06867     7 AGKSSEGGSGSYIVYVIrLGGSE---VKRRYSEFESLRKNLTRLYPTLIIPPIPEKHSLKDYakkpskaknDAKIIERRK 83

                          90       100
                  ....*....|....*....|....*.
gi 1034643448 354 KGLIWWMNHMASHPVLAQCDVFQHFL 379
Cdd:cd06867    84 RMLQRFLNRCLQHPILRNDIVFQKFL 109

The phosphoinositide binding Phox Homology domain of Sorting Nexins 20 and 21; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. This subfamily consists of SNX20, SNX21, and similar proteins. SNX20 interacts with P-Selectin glycoprotein ligand-1 (PSGL-1), a surface-expressed mucin that acts as a ligand for the selectin family of adhesion proteins. It may function in the sorting and cycling of PSGL-1 into endosomes. SNX21, also called SNX-L, is distinctly and highly-expressed in fetal liver and may be involved in protein sorting and degradation during embryonic liver development.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 291 GMKSYISYKLVPTHTQVP------VHRRYKHFDWLYARLAEKFP-VISVPHLPEKQATGRFEEDFISKRRKGLIWWMNHM 363
Cdd:cd07279    14 GEKKYVVYQLAVVQTGDPdtqpafIERRYSDFLKLYKALRKQHPqLMAKVSFPRKVLMGNFSSELIAERSRAFEQFLGHI 93

                          90
                  ....*....|....*....
gi 1034643448 364 ASHPVLAQCDVFQHFLTCP 382
Cdd:cd07279    94 LSIPNLRDSKAFLDFLQGP 112

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 1034643448   6 RALYDFRSENPGEISLREHEVLSLCSEQDiEGWLEGVNSRGDRGLFPA 53
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVLEKSE-DGWWKGRNKGGKEGLIPS 47

C-terminal Src Homology 3 domain of the Nebulin family of proteins; Nebulin family proteins contain multiple nebulin repeats, and may contain an N-terminal LIM domain and/or a C-terminal SH3 domain. They have molecular weights ranging from 34 to 900 kD, depending on the number of nebulin repeats, and they all bind actin. They are involved in the regulation of actin filament architecture and function as stabilizers and scaffolds for cytoskeletal structures with which they associate, such as long actin filaments or focal adhesions. Nebulin family proteins that contain a C-terminal SH3 domain include the giant filamentous protein nebulin, nebulette, Lasp1, and Lasp2. Lasp2, also called LIM-nebulette, is an alternatively spliced variant of nebulette. 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 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQDiEGWLEGVNSR-GDRGLFPASYVQ 57
Cdd:cd11789     1 RYRAMYDYAAADDDEVSFQEGDVIINVEIID-DGWMEGTVQRtGQSGMLPANYVE 54

First Src Homology 3 domain of Bzz1 and similar domains; Bzz1 (or Bzz1p) is a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Together with other proteins, it induces membrane scission in yeast. Bzz1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. This model represents the first C-terminal SH3 domain. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*
gi 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQDIEGWLEGVNSRGDRGLFPASYVQV 58
Cdd:cd11912     1 TAKVLYDYTASGDDEVSISEGEEVTVLEPDDGSGWTKVRNGSGEEGLVPTSYIEI 55

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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*..
gi 1034643448   4 RARALYDFRSENPGEISLREHEVLSL--CSEQDiegWLEGvNSRGDRGLFPASYVQV 58
Cdd:cd11805     1 RVQALYDFNPQEPGELEFRRGDIITVldSSDPD---WWKG-ELRGRVGIFPANYVQP 53

Src homology 3 domain of ArfGAP with SH3 domain, ankyrin repeat and PH domain containing proteins; ASAPs are Arf GTPase activating proteins (GAPs) and they function in regulating cell growth, migration, and invasion. They contain an N-terminal BAR domain, followed by a Pleckstrin homology (PH) domain, an Arf GAP domain, ankyrin (ANK) repeats, and a C-terminal SH3 domain. Vertebrates contain at least three members, ASAP1, ASAP2, and ASAP3, but some ASAP3 proteins do not seem to harbor a C-terminal SH3 domain. ASAP1 and ASAP2 show GTPase activating protein (GAP) activity towards Arf1 and Arf5. They do not show GAP activity towards Arf6, but are able to mediate Arf6 signaling by binding stably to GTP-Arf6. ASAP3 is an Arf6-specific GAP. 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 1034643448   4 RARALYDFRSENPGEISLREHEVLSLCSEQD---IEGWLEGVNSRgdRGLFPASY 55
Cdd:cd11821     1 RVRALYDCQADNDDELTFSEGEIIVVTGEEDdewWEGHIEGDPSR--RGVFPVSF 53

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 1034643448   4 RARALYDFRSENPGEISLREHEVLSLcSEQDIEGWLEGVNSrGDRGLFPASYVQVI 59
Cdd:pfam07653   1 YGRVIFDYVGTDKNGLTLKKGDVVKV-LGKDNDGWWEGETG-GRVGLVPSTAVEEI 54

The phosphoinositide binding Phox Homology domain of Sorting Nexin 1; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. Sorting nexins (SNXs) make up the largest group among PX domain containing proteins. They are involved in regulating membrane traffic and protein sorting in the endosomal system. The PX domain of SNXs binds PIs and targets the protein to PI-enriched membranes. SNXs differ from each other in PI-binding specificity and affinity, and the presence of other protein-protein interaction domains, which help determine subcellular localization and specific function in the endocytic pathway. SNX1 is both membrane associated and a cytosolic protein that exists as a tetramer in protein complexes. It can associate reversibly with membranes of the endosomal compartment, thereby coating these vesicles. SNX1 is a component of the retromer complex, a membrane coat multimeric complex required for endosomal retrieval of lysosomal hydrolase receptors to the Golgi. The retromer consists of a cargo-recognition subcomplex and a subcomplex formed by a dimer of sorting nexins (SNX1 and/or SNX2), which ensures efficient cargo sorting by facilitating proper membrane localization of the cargo-recognition subcomplex. SNX1 contains a Bin/Amphiphysin/Rvs (BAR) domain C-terminal to the PX domain. The PX domain of SNX1 specifically binds phosphatidylinositol-3-phosphate (PI3P) and PI(3,5)P2, while the BAR domain detects membrane curvature. Both domains help determine the specific membrane-targeting of SNX1, which is localized to a microdomain in early endosomes where it regulates cation-independent mannose-6-phosphate receptor retrieval to the trans Golgi network.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034643448 279 TIDDPTKQTKfkGMKSYISYKlVPTHTQVP--------VHRRYKHFDWLYARLAEKFPV--ISVPHLPEKQATGRFE--- 345
Cdd:cd07281     4 SITDPEKIGD--GMNAYVVYK-VTTQTSLLmfrskhftVKRRFSDFLGLYEKLSEKHSQngFIVPPPPEKSLIGMTKvkv 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 1034643448 346 --ED-----FISKRRKGLIWWMNHMASHPVLAQCDVFQHFL 379
Cdd:cd07281    81 gkEDsssaeFLERRRAALERYLQRIVSHPSLLQDPDVREFL 121