Seroatlas · Human Serome Atlas

XKR8

XK-related protein 8

Also known as: FLJ10307, XKR8_HUMAN

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

Protein identityUniProt · HPA

UniProt accession: Q9H6D3
Gene: XKR8
Ensembl: ENSG00000158156
Chromosome: 1
Canonical length: 395 aa
Protein class: Predicted membrane proteins, Transporters
Subcellular location: Golgi apparatus
Quaternary structure: Homodimer

OverviewNCBI Gene

Enables phospholipid scramblase activity. Involved in engulfment of apoptotic cell; phosphatidylserine exposure on apoptotic cell surface; and positive regulation of myoblast differentiation. Located in plasma membrane. [provided by Alliance of Genome Resources, Jul 2025]

Canonical amino-acid sequenceUniProt

395 residues, UniProt reviewed canonical sequence.

>Q9H6D3|XKR8
     1  MPWSSRGALL RDLVLGVLGT AAFLLDLGTD LWAAVQYALG GRYLWAALVL ALLGLASVAL
    61  QLFSWLWLRA DPAGLHGSQP PRRCLALLHL LQLGYLYRCV QELRQGLLVW QQEEPSEFDL
   121  AYADFLALDI SMLRLFETFL ETAPQLTLVL AIMLQSGRAE YYQWVGICTS FLGISWALLD
   181  YHRALRTCLP SKPLLGLGSS VIYFLWNLLL LWPRVLAVAL FSALFPSYVA LHFLGLWLVL
   241  LLWVWLQGTD FMPDPSSEWL YRVTVATILY FSWFNVAEGR TRGRAIIHFA FLLSDSILLV
   301  ATWVTHSSWL PSGIPLQLWL PVGCGCFFLG LALRLVYYHW LHPSCCWKPD PDQVDGARSL
   361  LSPEGYQLPQ NRRMTHLAQK FFPKAKDEAA SPVKG

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against XKR8 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: 8
Mean surface accessibility (rSASA): 0.3
Highest tissue expression: 23 nTPM

Expression across tissuesHPA

Tissue

choroid plexus: 23 nTPM
bone marrow: 21 nTPM
liver: 18 nTPM
pancreas: 16 nTPM
placenta: 14 nTPM
cerebellum: 11 nTPM

Single-cell type

cytotrophoblasts: 71 nCPM
migrating cytotrophoblasts: 36 nCPM
neutrophils: 35 nCPM
breast lactating cells: 23 nCPM
syncytiotrophoblasts: 19 nCPM
extravillous trophoblasts: 14 nCPM

Immune cell

eosinophil: 203 nTPM
neutrophil: 102 nTPM
basophil: 20 nTPM
memory CD4 T-cell: 16 nTPM
gdT-cell: 15 nTPM
MAIT T-cell: 15 nTPM

Brain region

hypothalamus: 15 nTPM
medulla oblongata: 14 nTPM
midbrain: 13 nTPM
cerebellum: 13 nTPM
choroid plexus: 13 nTPM
hippocampal formation: 13 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): 1.47
gnomAD pLI: 0
gnomAD missense Z: 1.46
DepMap mean gene effect: -0.2
DepMap dependency class: selective

Cancer expressionTCGA

Across TCGA tumor cohorts, this protein is over-expressed in roughly 4% of surveyed tumor types (aggregate summary; per-cohort expression, alteration, and survival load in the interactive view).

OntologyGO

Biological processes

Molecular functions

phospholipid scramblase activity

Cellular components

Protein domainsUniProt · Pfam · InterPro

KeywordsUniProt

InteractionsUniProt · HPA

Protein binding partners of XKR8 in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

Antibody and autoantibody relevanceSeroatlas analysis

Seroatlas reads XKR8 as an antibody target. Whether an autoantibody or antibody against XKR8 could matter depends on whether native XKR8 is physically reachable, whether the body needs it intact, and whether it acts in a disease-relevant tissue.

XKR8 is annotated at the cell surface, where native XKR8 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 XKR8 as an autoantigen. Seroatlas presents hypothesis context only and does not manufacture a known-serology claim.

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