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Reviewed, UniProtKB/Swiss-Prot P51811 (XK_HUMAN)

Last modified May 5, 2009. Version 73. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (6) | Third-party data | Customize display text xml rdf/xml gff fasta
Names and origin · Protein attributes · General annotation (Comments) · Ontologies · Sequence annotation (Features) · Sequences · References · Web resources · Cross-references · Entry information · Relevant documents

Names and origin

Protein namesRecommended name:
    Membrane transport protein XK
Alternative name(s):
    Kx antigen
    Kell complex 37 kDa component
    XK-related protein 1
Gene names
Name: XK
Synonyms: XKR1, XRG1
OrganismHomo sapiens (Human)
Taxonomic identifier9606 [NCBI]
Taxonomic lineageEukaryotaMetazoaChordataCraniataVertebrataEuteleostomiMammaliaEutheriaEuarchontogliresPrimatesHaplorrhiniCatarrhiniHominidaeHomo

Protein attributes

Sequence length444 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is not processed.
Protein existenceEvidence at protein level.

General annotation (Comments)

Function

May be involved in sodium-dependent transport of neutral amino acids or oligopeptides.

Subunit structure

Heterodimer with Kell; disulfide-linked. Ref.7

Subcellular location

Membrane; Multi-pass membrane protein Potential.

Tissue specificity

High levels in skeletal muscle, heart, brain, and pancreas; low levels in placenta, lung, liver, and kidney.

Post-translational modification

Not glycosylated. Ref.6

Polymorphism

XK is responsible for the Kx blood group system.

Involvement in disease

Defects in XK are the cause of McLeod syndrome (MLS) [MIM:314850]. It is an X-linked multisystem disorder characterized by late onset abnormalities in the neuromuscular and hematopoietic systems. Ref.9 Ref.10 Ref.11

Sequence similarities

Belongs to the XK family.

Ontologies

Keywords
   Biological processAmino-acid transport
Transport
   Cellular componentMembrane
   DiseaseDisease mutation
   DomainTransmembrane
   Molecular functionBlood group antigen
   PTMDisulfide bond
Phosphoprotein
   Technical termDirect protein sequencing
Gene Ontology (GO)
   Biological processamino acid transport

Inferred from electronic annotation. Source: UniProtKB-KW

   Cellular componentintegral to membrane Ref.1

Traceable author statement. Source: HGNC

   Molecular functionprotein binding Ref.6

Inferred from physical interaction. Source: HGNC

transporter activity Ref.1

Traceable author statement. Source: ProtInc

Complete GO annotation...

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 444444Membrane transport protein XK
PRO_0000190767

Regions

Topological domain1 – 22Cytoplasmic Potential
Transmembrane3 – 2321 Potential
Topological domain24 – 3714Extracellular Potential
Transmembrane38 – 5821 Potential
Topological domain59 – 6810Cytoplasmic Potential
Transmembrane69 – 8921 Potential
Topological domain90 – 14051Extracellular Potential
Transmembrane141 – 16121 Potential
Topological domain162 – 17110Cytoplasmic Potential
Transmembrane172 – 19221 Potential
Topological domain193 – 20816Extracellular Potential
Transmembrane209 – 22921 Potential
Topological domain230 – 2356Cytoplasmic Potential
Transmembrane236 – 25621 Potential
Topological domain257 – 27721Extracellular Potential
Transmembrane278 – 29821 Potential
Topological domain299 – 31719Cytoplasmic Potential
Transmembrane318 – 33821 Potential
Topological domain339 – 34911Extracellular Potential
Transmembrane350 – 37021 Potential
Topological domain371 – 44474Cytoplasmic Potential

Amino acid modifications

Modified residue631Phosphoserine Ref.8
Disulfide bond347Interchain (with C-72 in Kell) Ref.7

Natural variations

Natural variant2221R → G in MLS. Ref.10
VAR_013817
Natural variant2941C → R in MLS. Ref.9
VAR_013818
Natural variant3271E → K in MLS; atypical without hematologic, neuromuscular, or cerebral involvement; protein seems functional. Ref.11
VAR_023581

Experimental info

Mutagenesis3471C → S: Loss of Kell-XK complex. Ref.7
Sequence conflict2481F → L Ref.3
Sequence conflict2481F → L Ref.5

Sequences

Sequence LengthMass (Da)Tools
P51811-1 [UniParc].

Last modified January 24, 2006. Version 5.
Checksum: 6F90B0B45659A1DA

FASTA44450,902
        10         20         30         40         50         60 
MKFPASVLAS VFLFVAETTA ALSLSSTYRS GGDRMWQALT LLFSLLPCAL VQLTLLFVHR 

        70         80         90        100        110        120 
DLSRDRPLVL LLHLLQLGPL FRCFEVFCIY FQSGNNEEPY VSITKKRQMP KNGLSEEIEK 

       130        140        150        160        170        180 
EVGQAEGKLI THRSAFSRAS VIQAFLGSAP QLTLQLYISV MQQDVTVGRS LLMTISLLSI 

       190        200        210        220        230        240 
VYGALRCNIL AIKIKYDEYE VKVKPLAYVC IFLWRSFEIA TRVVVLVLFT SVLKTWVVVI 

       250        260        270        280        290        300 
ILINFFSFFL YPWILFWCSG SPFPENIEKA LSRVGTTIVL CFLTLLYTGI NMFCWSAVQL 

       310        320        330        340        350        360 
KIDSPDLISK SHNWYQLLVY YMIRFIENAI LLLLWYLFKT DIYMYVCAPL LVLQLLIGYC 

       370        380        390        400        410        420 
TAILFMLVFY QFFHPCKKLF SSSVSEGFQR WLRCFCWACR QQKPCEPIGK EDLQSSRDRD 

       430        440 
ETPSSSKTSP EPGQFLNAED LCSA 

« Hide

References

« Hide 'large scale' references
[1]"Isolation of the gene for McLeod syndrome that encodes a novel membrane transport protein."
Ho M., Chelly J., Carter N., Danek A., Crocker P., Monaco A.P.
Cell 77:869-880(1994) [PubMed: 8004674] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [MRNA].
[2]Ho M.
Submitted (MAY-1999) to the EMBL/GenBank/DDBJ databases
Cited for: SEQUENCE REVISION TO 204-205.
[3]"A superfamily of XK-related genes (XRG) widely expressed in vertebrates and invertebrates."
Huang C.-H., Chen Y.
Submitted (JAN-2004) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [MRNA].
[4]SeattleSNPs variation discovery resource
Submitted (MAY-2005) to the EMBL/GenBank/DDBJ databases
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[5]"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
The MGC Project Team
Genome Res. 14:2121-2127(2004) [PubMed: 15489334] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
Tissue: Testis.
[6]"Purification and partial characterization of the erythrocyte Kx protein deficient in McLeod patients."
Khamlichi S., Bailly P., Blanchard D., Goossens D., Cartron J.-P., Bertrand O.
Eur. J. Biochem. 228:931-934(1995) [PubMed: 7737196] [Abstract]
Cited for: PROTEIN SEQUENCE OF 1-22, LACK OF GLYCOSYLATION.
[7]"Association of XK and Kell blood group proteins."
Russo D., Redman C., Lee S.
J. Biol. Chem. 273:13950-13956(1998) [PubMed: 9593744] [Abstract]
Cited for: SUBUNIT, DISULFIDE BOND, MUTAGENESIS OF CYS-347.
[8]"Global, in vivo, and site-specific phosphorylation dynamics in signaling networks."
Olsen J.V., Blagoev B., Gnad F., Macek B., Kumar C., Mortensen P., Mann M.
Cell 127:635-648(2006) [PubMed: 17081983] [Abstract]
Cited for: PHOSPHORYLATION [LARGE SCALE ANALYSIS] AT SER-63, MASS SPECTROMETRY.
Tissue: Epithelium.
[9]"McLeod neuroacanthocytosis: genotype and phenotype."
Danek A., Rubio J.P., Rampoldi L., Ho M., Dobson-Stone C., Tison F., Symmans W.A., Oechsner M., Kalckreuth W., Watt J.M., Corbett A.J., Hamdalla H.H., Marshall A.G., Sutton I., Dotti M.T., Malandrini A., Walker R.H., Daniels G., Monaco A.P.
Ann. Neurol. 50:755-764(2001) [PubMed: 11761473] [Abstract]
Cited for: VARIANT MLS ARG-294.
[10]"Point mutations causing the McLeod phenotype."
Russo D.C., Lee S., Reid M.E., Redman C.M.
Transfusion 42:287-293(2002) [PubMed: 11961232] [Abstract]
Cited for: VARIANT MLS GLY-222.
[11]"McLeod phenotype associated with a XK missense mutation without hematologic, neuromuscular, or cerebral involvement."
Jung H.H., Hergersberg M., Vogt M., Pahnke J., Treyer V., Rothlisberger B., Kollias S.S., Russo D., Frey B.M.
Transfusion 43:928-938(2003) [PubMed: 12823753] [Abstract]
Cited for: VARIANT MLS LYS-327.
+Additional computationally mapped references.

Cross-references

Sequence databases

Z32684 mRNA. Translation: CAA83632.2.
AY534238 mRNA. Translation: AAT07087.1.
DQ062746 Genomic DNA. Translation: AAY43132.1.
BC036019 mRNA. Translation: AAH36019.1.
IPIIPI00020896.
PIRI39294.
RefSeqNP_066569.1.
UniGeneHs.78919

3D structure databases

ModBaseSearch...

Protein family/group databases

TCDB9.B.5.1.1. KX blood-group antigen (KXA) family.

Proteomic databases

PRIDEP51811.

Genome annotation databases

EnsemblENSG00000047597. Homo sapiens. [Contig view]
GeneID7504.
KEGGhsa:7504.

Organism-specific databases

GeneCardsGC0XP037430.
H-InvDBHIX0028449.
HGNCHGNC:12811. XK.
MIM314850. gene+phenotype.
Orphanet59306. McLeod neuroacanthocytosis syndrome.
PharmGKBPA33162.
GenAtlasSearch...

Phylogenomic databases

HOGENOMP51811.
HOVERGENP51811.
OMAP51811. GKLFTHR.

Gene expression databases

ArrayExpressP51811.
BgeeP51811.
CleanExHS_XK.
GermOnlineENSG00000047597. Homo sapiens.

Family and domain databases

InterProIPR018629. Membr_transp_prot_XK-like.
[Graphical view]
PfamPF09815. XK-related. 1 hit.
[Graphical view]
ProtoNetSearch...

Other Resources

NextBio29381.
SOURCESearch...

Entry information

Entry nameXK_HUMAN
AccessionPrimary (citable) accession number: P51811
Secondary accession number(s): Q4TTN6, Q8IUK6, Q9UC77
Entry history
Integrated into UniProtKB/Swiss-Prot: October 1, 1996
Last sequence update: January 24, 2006
Last modified: May 5, 2009
This is version 73 of the entry and version 5 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation projectHPI (Human Proteome Initiative)

Relevant documents

Blood group antigen proteins

Nomenclature of blood group antigens and list of entries

Human chromosome X

Human chromosome X: entries, gene names and cross-references to MIM

Human entries with polymorphisms or disease mutations

List of human entries with polymorphisms or disease mutations

Human polymorphisms and disease mutations

Index of human polymorphisms and disease mutations

MIM cross-references

Online Mendelian Inheritance in Man (MIM) cross-references in UniProtKB/Swiss-Prot

SIMILARITY comments

Index of protein domains and families

Names and origin · Protein attributes · General annotation (Comments) · Ontologies · Sequence annotation (Features) · Sequences · References · Web resources · Cross-references · Entry information · Relevant documents