Seroatlas · Human Serome Atlas

XKRX

XK-related protein 2

Also known as: XKR2, XKR2_HUMAN, XPLAC

Cross-references: UniProt · Ensembl · Human Protein Atlas · GeneCards · NCBI Gene

Protein identityUniProt · HPA

UniProt accession: Q6PP77
Gene: XKRX
Ensembl: ENSG00000182489
Chromosome: X
Canonical length: 449 aa
Protein class: Predicted membrane proteins, Transporters

OverviewNCBI Gene

This gene encodes a protein that is related to a component of the XK/Kell complex of the Kell blood group system. The encoded protein includes several transmembrane domains, is known to be exposed to the cell surface, and may function as a membrane transporter. [provided by RefSeq, May 2010]

Canonical amino-acid sequenceUniProt

449 residues, UniProt reviewed canonical sequence.

>Q6PP77|XKRX
     1  MDRVYEIPEE PNVDPVSSLE EDVIRGANPR FTFPFSILFS TFLYCGEAAS ALYMVRIYRK
    61  NSETYWMTYT FSFFMFSSIM VQLTLIFVHR DLAKDKPLSL FMHLILLGPV IRCLEAMIKY
   121  LTLWKKEEQE EPYVSLTRKK MLIDGEEVLI EWEVGHSIRT LAMHRNAYKR MSQIQAFLGS
   181  VPQLTYQLYV SLISAEVPLG RVVLMVFSLV SVTYGATLCN MLAIQIKYDD YKIRLGPLEV
   241  LCITIWRTLE ITSRLLILVL FSATLKLKAV PFLVLNFLII LFEPWIKFWR SGAQMPNNIE
   301  KNFSRVGTLV VLISVTILYA GINFSCWSAL QLRLADRDLV DKGQNWGHMG LHYSVRLVEN
   361  VIMVLVFKFF GVKVLLNYCH SLIALQLIIA YLISIGFMLL FFQYLHPLRS LFTHNVVDYL
   421  HCVCCHQHPR TRVENSEPPF ETEARQSVV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against XKRX can act on the native protein depends on physical access: surface and secreted proteins are reachable by circulating antibodies, intracellular proteins usually are not.

Antibody reachability: Cell surface
Secreted: No
Transmembrane segments: 10
Mean surface accessibility (rSASA): 0.32
Highest tissue expression: 9.3 nTPM

Expression across tissuesHPA

Tissue

skin: 9.3 nTPM
tonsil: 3.2 nTPM
small intestine: 2.3 nTPM
esophagus: 2.2 nTPM
thymus: 1.7 nTPM
vagina: 1.6 nTPM

Single-cell type

adrenal medulla cells: 21 nCPM
respiratory deuterosomal cells: 18 nCPM
pituicytes/fscs: 17 nCPM
transitional alveolar cells: 14 nCPM
esophageal apical cells: 13 nCPM
alveolar cells type 1: 10 nCPM

Immune cell

naive B-cell: 1.9 nTPM
naive CD4 T-cell: 1.5 nTPM
naive CD8 T-cell: 1.2 nTPM
MAIT T-cell: 0.2 nTPM
memory B-cell: 0.2 nTPM
total PBMC: 0.2 nTPM

Brain region

hypothalamus: 4 nTPM
amygdala: 1.3 nTPM
midbrain: 1.2 nTPM
pons: 1 nTPM
basal ganglia: 0.9 nTPM
cerebral cortex: 0.9 nTPM

Genetic constraint and essentialitygnomAD · DepMap

Does the body need this protein intact? Low LOEUF or a strong DepMap dependency means loss or blockade of the protein is likely to be felt.

gnomAD LOEUF (loss-of-function intolerance): 1.16
gnomAD pLI: 0
gnomAD missense Z: 0.48
DepMap mean gene effect: 0.02
DepMap dependency class: none

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 5% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Cellular components

plasma membrane

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads XKRX as an antibody target. Whether an autoantibody or antibody against XKRX could matter depends on whether native XKRX is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

XKRX is annotated at the cell surface, where native XKRX is exposed to circulating antibodies and is a prime autoantibody target that could block, deplete, or overstimulate it.

Annotation status

The present source text does not explicitly label XKRX as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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