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P51811 (XK_HUMAN) Reviewed, UniProtKB/Swiss-Prot

Last modified July 9, 2014. Version 117. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (6) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Web links·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

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

Protein attributes

Sequence length444 AA.
Sequence statusComplete.
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

McLeod syndrome (MLS) [MIM:300842]: A multisystem disorder characterized by the absence of red blood cell Kx antigen, weak expression of Kell red blood cell antigens, acanthocytosis, and compensated hemolysis. Most carriers of this McLeod blood group phenotype have acanthocytosis and elevated serum creatine kinase levels and are prone to develop a severe neurologic disorder resembling Huntington disease. Additional symptoms include generalized seizures, neuromuscular symptoms leading to weakness and atrophy, and cardiomyopathy mainly manifesting with atrial fibrillation, malignant arrhythmias, and dilated cardiomyopathy.
Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.8 Ref.9 Ref.10

Sequence similarities

Belongs to the XK family.

Ontologies

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 444444Membrane transport protein XK
PRO_0000190767

Regions

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

Amino acid modifications

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

Natural variations

Natural variant2221R → G in MLS. Ref.9
VAR_013817
Natural variant2941C → R in MLS. Ref.8
Corresponds to variant rs28933690 [ dbSNP | Ensembl ].
VAR_013818
Natural variant3271E → K in MLS; atypical without hematologic, neuromuscular, or cerebral involvement; protein seems functional. Ref.10
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 [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] [Europe PMC] [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] [Europe PMC] [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] [Europe PMC] [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] [Europe PMC] [Abstract]
Cited for: SUBUNIT, DISULFIDE BOND, MUTAGENESIS OF CYS-347.
[8]"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] [Europe PMC] [Abstract]
Cited for: VARIANT MLS ARG-294.
[9]"Point mutations causing the McLeod phenotype."
Russo D.C., Lee S., Reid M.E., Redman C.M.
Transfusion 42:287-293(2002) [PubMed] [Europe PMC] [Abstract]
Cited for: VARIANT MLS GLY-222.
[10]"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] [Europe PMC] [Abstract]
Cited for: VARIANT MLS LYS-327.
+Additional computationally mapped references.

Web resources

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
Z32684 mRNA. Translation: CAA83632.2.
AY534238 mRNA. Translation: AAT07087.1.
DQ062746 Genomic DNA. Translation: AAY43132.1.
BC036019 mRNA. Translation: AAH36019.1.
CCDSCCDS14241.1.
PIRI39294.
RefSeqNP_066569.1. NM_021083.2.
UniGeneHs.78919.

3D structure databases

ProteinModelPortalP51811.
ModBaseSearch...
MobiDBSearch...

Protein-protein interaction databases

BioGrid113341. 4 interactions.
IntActP51811. 1 interaction.
STRING9606.ENSP00000367879.

Protein family/group databases

TCDB2.A.112.1.1. 2.a.112. the kx blood-group antigen (kxa) family.

PTM databases

PhosphoSiteP51811.

Polymorphism databases

DMDM85700269.

Proteomic databases

MaxQBP51811.
PaxDbP51811.
PRIDEP51811.

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Genome annotation databases

EnsemblENST00000378616; ENSP00000367879; ENSG00000047597.
ENST00000601300; ENSP00000469825; ENSG00000269380.
GeneID7504.
KEGGhsa:7504.
UCSCuc004ddq.3. human.

Organism-specific databases

CTD7504.
GeneCardsGC0XP037545.
GeneReviewsXK.
HGNCHGNC:12811. XK.
HPAHPA019036.
MIM300842. phenotype.
314850. gene.
neXtProtNX_P51811.
Orphanet59306. McLeod neuroacanthocytosis syndrome.
PharmGKBPA37410.
GenAtlasSearch...

Phylogenomic databases

eggNOGNOG149424.
HOGENOMHOG000118070.
HOVERGENHBG055838.
InParanoidP51811.
OMATYRSAGD.
OrthoDBEOG7034H1.
PhylomeDBP51811.
TreeFamTF331465.

Gene expression databases

ArrayExpressP51811.
BgeeP51811.
CleanExHS_XK.
GenevestigatorP51811.

Family and domain databases

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

Other

GenomeRNAi7504.
NextBio29381.
PROP51811.
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: July 9, 2014
This is version 117 of the entry and version 5 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programChordata Protein Annotation Program
DisclaimerAny medical or genetic information present in this entry is provided for research, educational and informational purposes only. It is not in any way intended to be used as a substitute for professional medical advice, diagnosis, treatment or care.

Relevant documents

SIMILARITY comments

Index of protein domains and families

MIM cross-references

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

Human polymorphisms and disease mutations

Index of human polymorphisms and disease mutations

Human entries with polymorphisms or disease mutations

List of human entries with polymorphisms or disease mutations

Human chromosome X

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

Blood group antigen proteins

Nomenclature of blood group antigens and list of entries