Conserved Protein Domain Family
SPX

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pfam03105: SPX 
SPX domain
We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that all the members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors PHO81 from Saccharomyces cerevisiae and NUC-2 from Neurospora crassa, are also members of this family. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2 NUC-2 contains several ankyrin repeats pfam00023. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with murine xenotropic and polytropic leukaemia viruses (MLV). Infection by these retroviruses can inhibit XPR1-mediated cAMP signalling and result in cell toxicity and death. The similarity between SYG1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae, and many other diverse organisms. In addition, given the similarities between XPR1 and SYG1 and phosphate regulatory proteins, it has been proposed that XPR1 might be involved in G-protein associated signal transduction and may itself function as a phosphate sensor.
Statistics
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PSSM-Id: 397293
Aligned: 206 rows
Threshold Bit Score: 80.6891
Threshold Setting Gi: 557738333
Created: 20-May-2020
Updated: 7-Aug-2020
Structure
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Aligned Rows:
PubMed ReferencesClick to see Conserved Features Help

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
EKC99484        1 MKFGRYLEENATPEWKRAYIDYRGAKKAIK----RAAA-SREnqavdenndfsseedda-------------dngpsakp 62   Trichosporon ...
CCH59267        1 MKFAKLFSCYQIPEWYEHYLDYRGFKKLIK----EINI------------------------------------------ 34   Tetrapisispor...
ESS34272        1 MKFGAKLRAYALPEWRAAYIDYGALKSLLK----QLQR-EIDsaeaqedrirekwrr------------------wnekl 57   Toxoplasma go...
EGG14759        1 MKFGKYLENNQVPEWKDKYVSYKQLRKNIK----RFKS-EIE-------------------------------------- 37   Cavenderia fa...
Q86HQ3          1 MKFRDYLKDNKVSHWRDKYIDYEYLKNLIDn---EYINaEIL-------------------------------------- 39   Dictyostelium...
Q54HI2          1 MKFRDLLNDHIISHWRDKYIDYEYLKDLIDreyhNAPN-SLNnsmmidmsqsinntiaeqysvndissmvtkggindspt 79   Dictyostelium...
EGC32499        1 MKFREYLNSHIVSHWRDKYLDYEYLKQLID----KEYNnAPNsldnsaiidftqs---------------------iadq 55   Dictyostelium...
CCK69919        1 MKFADHLRESAIPEWRDKYIDYKLGKKKLKyeyeSVSR-DPL-------------------------------------- 41   Kazachstania ...
XP_001645563    1 MRFGDFITESAIPEWKGKYIQYNTGKKRLK----EFAE------------------------------------------ 34   Vanderwaltozy...
XP_654561       1 MKFAQKFNEGMTVEWEDQYVDYNLLCRKLN----SIQT------------------------------------------ 34   Entamoeba his...
EKC99484       63 rspnspsalTRIISGSPRTPNTARSGKTPRTGPsplsprpkrsvgkspaagpsgtrvsetvrwagasgqtvtarsfesle 142  Trichosporon ...
CCH59267       35 ---------IQDTLFYEKYYNNQ--------------------------------------------------------- 48   Tetrapisispor...
ESS34272       58 ektrskeaeGHPGICDAATDEPESAPHVVANAPaspa------------------------------------------- 94   Toxoplasma go...
EGG14759       38 ---------SIIKSNNNDSSSNHKLEN----------------------------------------------------- 55   Cavenderia fa...
Q86HQ3         40 ---------NSAIIDLPLSPEEQNNINKN--------------------------------------------------- 59   Dictyostelium...
Q54HI2         80 tdievdetaDSPAIPSPIISHSNINSNNNNNGGtnsvgfshlhrqln-------------------------rqnsnlkn 134  Dictyostelium...
EGC32499       56 hhtsiinqlSESGSNNINTQDEDHIKSYFKNKTpqlqp------------------------------------------ 93   Dictyostelium...
CCK69919          --------------------------------------------------------------------------------      Kazachstania ...
XP_001645563      --------------------------------------------------------------------------------      Vanderwaltozy...
XP_654561      35 ---------LKNQLGDMQHE------------------------------------------------------------ 45   Entamoeba his...
EKC99484      143 shrlsVPDSRDRHHADTQPSP--GYGATGTSPPLDDNGVQFPPPLDLGepgippspdlkssqqtaflepsdlnkerlkgr 220  Trichosporon ...
CCH59267       49 -----NNEGNTGGEYNSEEDKllVDGRKSEPPRKRRDGTILGDNIDVN-------------------------------- 91   Tetrapisispor...
ESS34272       95 -aadsGSTRLSTACHESSNSS--PSPGVVSSSSSSSSSSSSSSSSSSSs------------------------------- 140  Toxoplasma go...
EGG14759       56 -----EQDNNNNNNISGQLKR--TYSSIILNKSNLFNPLPSTTPSSPI-------------------------------- 96   Cavenderia fa...
Q86HQ3         60 -----NNNNNNNNNNNNNNNN--NNNNINNNNNNNNTLKDGEQTNSNNisipn--------------------------- 105  Dictyostelium...
Q54HI2        135 ssnsiNLLKADDSNNIEKHVK--SYFDQRNNNNNINNINNNNNNNSNNsnnsnnnktikntrniiad------------- 199  Dictyostelium...
EGC32499       94 -phsqPLPPPPPLQQQQQQSQ--SSPTSPQQLNIPNHHLHHNRFHSHNirdedtt------------------------- 145  Dictyostelium...
CCK69919       42 -----KVVVTAASGDSAVDVE--RVGGPVDTEYGPQVHDEPSDPQLTD-------------------------------- 82   Kazachstania ...
XP_001645563   35 -----LLSKEETLEDSQHLIE--AFPTEFLGPSRPLATSDRGHSHPRF-------------------------------- 75   Vanderwaltozy...
XP_654561      46 -----VEDIVIEMSDESNSAK--EDNSTEPQSPGGQFCEEGGEGDYTM-------------------------------- 86   Entamoeba his...
EKC99484      221 vdtargasgatsgatsgaasgatsgsasgaasgsrspaissipetpaegeergtsseggpsspdapdtpltqssrkhhGH 300  Trichosporon ...
CCH59267          --------------------------------------------------------------------------------      Tetrapisispor...
ESS34272      141 -----------------------------------------------------------------------------sSS 143  Toxoplasma go...
EGG14759          --------------------------------------------------------------------------------      Cavenderia fa...
Q86HQ3        106 -------------------------------------------------------------------------qmapqES 112  Dictyostelium...
Q54HI2        200 ------------------------------------------------------------ddggnedttlgspfsspsIG 219  Dictyostelium...
EGC32499      146 ------------------------------------------------------------------------lgsaspFS 153  Dictyostelium...
CCK69919          --------------------------------------------------------------------------------      Kazachstania ...
XP_001645563      --------------------------------------------------------------------------------      Vanderwaltozy...
XP_654561         --------------------------------------------------------------------------------      Entamoeba his...
EKC99484      301 TKGSPSKFSFKSPKThasvgvsqsstadapsQKKSLRNMKLPSPKIQPkqpqsmdelyatlnpDERAFFD--HLDKQLDK 378  Trichosporon ...
CCH59267       92 -----KEEDSFFNNE-----------------------------EIKE---------------RVHFFIL--EFNKEIED 120  Tetrapisispor...
ESS34272      144 SSSSSSAVAHSASSLfyfsawwgggeeiggrGVEDSRAEEAREAESVRrvr----------eaAVDAFDS--RLESEVEK 211  Toxoplasma go...
EGG14759       97 ---PRQQQQQQLPNP------------------------------------------------VDLQLLL--INQKQMQS 123  Cavenderia fa...
Q86HQ3        113 SGEDEDDENENGNGV-----------------VGDEDGGDDDEI-------------------EMDEL----VIDDNGEI 152  Dictyostelium...
Q54HI2        220 SPPMSSPSPKMLKQElhsp---------lltSEKDEDEEEEGEE-------------------EEDIEMEqlELDDHDKN 271  Dictyostelium...
EGC32499      154 NSSVGSPRPKAKSEL--------------------NSPLLSDQD-------------------NDEIEMEqiNLDSSNNN 194  Dictyostelium...
CCK69919       83 -----------FQRK------------------------------------------------AIKDFIEnwVIGVELVK 103  Kazachstania ...
XP_001645563   76 ------SRYSYLQNE------------------------------------------------FIREFIDhwLISQEISK 101  Vanderwaltozy...
XP_654561      87 ----------LTTKIa----------------------------------------------tEEQNFWK--EFDFNIEK 108  Entamoeba his...
EKC99484      379 VETFYSAREQEATRRFS--QLKDQLNAL-AE------HRRIFHEQFpggqheweskvgrvtknahvpilakavqhlhgrn 449  Trichosporon ...
CCH59267      121 IENFYLQHYNLYCSRLNllILSTQFNDI-LPllsthsYLNEKILELkqfcd-------------------------sfns 174  Tetrapisispor...
ESS34272      212 VAAHFNEELVFLVDRLQ--AVEAELKAI-------------EVREG---------------------------------- 242  Toxoplasma go...
EGG14759      124 HND-SSLYNQYQSNQFT----KTTLTRL---------QEIQ--------------------------------------- 150  Cavenderia fa...
Q86HQ3        153 INITATAGSRVKVKK----GINKGVKRL---------KKIAKNTNNrlsrmv-----------------------srspk 196  Dictyostelium...
Q54HI2        272 TTINMTANGSRGNLRKGmnQFVKTIPQNiKQ------LNSQISNSFlkf----------------------------ggm 317  Dictyostelium...
EGC32499      195 NNTNNKNNNNNNNIILN--NKNESYANL---------KKAGIYNLNknlsy-------------------------nnln 238  Dictyostelium...
CCK69919      104 CNEFYQWLLDDCRQKFT--VLQKQIQIYhIQqq---nYQNEFMEGEndg----------------------------mia 150  Kazachstania ...
XP_001645563  102 CNDFFLWLLEQCQNRYE--MLQKQVLLY---------KRHGDLSYS---------------------------------- 136  Vanderwaltozy...
XP_654561     109 IDVFYCDRLKESCRFIN--DFYDRLMAFgLV------DPKQHKKEKfqpiyk----------------------qlvahe 158  Entamoeba his...
EKC99484      450 PFHNH-TDDENAGGSGANSANGGngang-------------------trrrSPAGMPGASNGNTPSNGGTAYSta---vs 506  Trichosporon ...
CCH59267      175 TITDK--SDNPVYYNPSNKDMLKsss----------------------latNSNSSNSASVNNLKLPNLI---------- 220  Tetrapisispor...
ESS34272      243 RTAAA-EAEEGSAGEEGGEDAGKplr----------------------detVQEGGE----------------------- 276  Toxoplasma go...
EGG14759      151 EEFIQlCIGEAEKNSKSEKEELmnq-----------------------meeTEETLE----------------------- 184  Cavenderia fa...
Q86HQ3        197 NKGLG--SSSEIEGDEFQLDGGGiss----------------------qieMVASNNITGATVFVPQETFQDG------- 245  Dictyostelium...
Q54HI2        318 VKGDK-SNDKNNDKSNDKNNNKNnknnnnn---------------nnlndeDNFDMMTSQIEKVLNNKDNMKLmesctft 381  Dictyostelium...
EGC32499      239 KNISF-NNLNQLHNSGNINNSVNmnksmshgnfdglsrtsshlnlevltsqIEKVMESRENMELMESGIIQQQenf-qti 316  Dictyostelium...
CCK69919      151 NSHAT-STTSLDLSSEQHVNPYGtig-----------------------edSVRSRRDTAWTRFKELLDDNKLlps-wpk 205  Kazachstania ...
XP_001645563  137 VHGSLlASQRSFVKKGTQSSYGSltsllk----------------yadeqkASCSKQKPKSAVKMTSRVKEFLr------ 194  Vanderwaltozy...
XP_654561     159 KKGIKkVLKYNNGDSENSRENKRnqrkslkiaasmfqeteevggsldvidlAASTLKHARSRRGTISREGSFNss---ds 235  Entamoeba his...
EKC99484      507 SVRQPEGGsngsngsgsegssgDNDLSGT-----TAAGSTRVLPGkp-------kqFDPERYQKYKK--ELRTAVVEYYR 572  Trichosporon ...
CCH59267      221 DYDLANNN--------------SATISGI-----NGYPYSTSSNNsqvs---ttilNNNLQIIDEIE--EILNFLLDLRL 276  Tetrapisispor...
ESS34272      277 EITDKEVA--------------KSERRVF-----FDTHVREGENA------------QREATTAYLR--RHERVVLSILD 323  Toxoplasma go...
EGG14759      185 SQTISIQM--------------DQLGVED-----DETELEDGANN-----------NNNNNIDSSKI-------ILEYYK 227  Cavenderia fa...
Q86HQ3        246 FIDQVNKVdiffv-----dryrKTKFKCV-----DLVGMIPFLSD-------------NEQLRTIRNidYVKQGFHDNYH 302  Dictyostelium...
Q54HI2        382 TKENFQTAfv----------dqVNKVDSF-----FVERYRKTKEKcvelcnmipflSTNEQLRTIRNieFVKQGFQDNYH 446  Dictyostelium...
EGC32499      317 FIDQVNKV--------------DTFFVER-----YRKTKKKCVELcnmi----pflSTKEQYRTIRNidYVKQGLHDNYH 373  Dictyostelium...
CCK69919      206 NSTKLKDLilk---------lqGEHGEQI-----SNTVKDTFAYNnl-------ntVSEMTIKQAQH--LLSDAILEYYL 262  Kazachstania ...
XP_001645563  195 HSNLLPSI--------------PQSLKHY-----FRFTSTECSCAst--------qFSDITIIKARR--MLDDALLELYL 245  Vanderwaltozy...
XP_654561     236 KKKGSSTIsseedstdstvktnEGSEEGGnsdnnEGICEEDLLDLe---------kEHSEISRRKRN--KLRTAAEEYYR 304  Entamoeba his...
EKC99484      573 QLELIKNYRILNLTGFRKALKKFEKVTGIHCLDLYTDER 611  Trichosporon asahii var. asahii CBS 8904
CCH59267      277 NYRNLKLFKEMNKRALFKLIKKVHKKIGY-------NMD 308  Tetrapisispora blattae CBS 6284
ESS34272      324 TLEKLEGFAKLNMICVYKILKKRDKKLKTHLLQDAFERY 362  Toxoplasma gondii VEG
EGG14759      228 FLNLLKNYKIFNYTGFIKILKKAEKNLELNLNDRILTRL 266  Cavenderia fasciculata
Q86HQ3        303 YLESLESYKNLNLDGFYKILDKYEKINPR-----IAKEC 336  Dictyostelium discoideum
Q54HI2        447 YLESLEAFKELNIKGFKKVLEKYEKKNRI-----ISSEC 480  Dictyostelium discoideum
EGC32499      374 YLEMLESFKDVNIKGFNKVLNKYEKKNRL-----IANEC 407  Dictyostelium purpureum
CCK69919      263 FLQMVKTYRDLNVTGFRKMVKKFDKTLHTQELSKFMDFG 301  Kazachstania naganishii CBS 8797
XP_001645563  246 YIELVRTFRNVNATGVRKIVKKFDKICKTHELKYVIQDV 284  Vanderwaltozyma polyspora DSM 70294
XP_654561     305 GLLLMQNFCSLNNEAIIKILKKSDKITGY----DRMETI 339  Entamoeba histolytica HM-1:IMSS
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