CD8A

Protein identityUniProt · HPA

UniProt accession

P01732

Gene

CD8A

Ensembl

ENSG00000153563

Chromosome

2

Canonical length

235 aa

Protein class

CD markers, Disease related genes, Human disease related genes, Predicted intracellular proteins, Predicted membrane proteins

Subcellular location

Plasma membrane

Secretome location

Intracellular and membrane

Quaternary structure

Homodimer

OverviewNCBI Gene

The CD8 antigen is a cell surface glycoprotein found on most cytotoxic T lymphocytes that mediates efficient cell-cell interactions within the immune system. The CD8 antigen acts as a coreceptor with the T-cell receptor on the T lymphocyte to recognize antigens displayed by an antigen presenting cell in the context of class I MHC molecules. The coreceptor functions as either a homodimer composed of two alpha chains or as a heterodimer composed of one alpha and one beta chain. Both alpha and beta chains share significant homology to immunoglobulin variable light chains. This gene encodes the CD8 alpha chain. Multiple transcript variants encoding different isoforms have been found for this gene. The major protein isoforms of this gene differ by the presence or absence of a transmembrane domain and thus differ in being a membrane-anchored or secreted protein. [provided by RefSeq, May 2020]

Canonical amino-acid sequenceUniProt

235 residues, UniProt reviewed canonical sequence.

>P01732|CD8A
     1  MALPVTALLL PLALLLHAAR PSQFRVSPLD RTWNLGETVE LKCQVLLSNP TSGCSWLFQP
    61  RGAAASPTFL LYLSQNKPKA AEGLDTQRFS GKRLGDTFVL TLSDFRRENE GYYFCSALSN
   121  SIMYFSHFVP VFLPAKPTTT PAPRPPTPAP TIASQPLSLR PEACRPAAGG AVHTRGLDFA
   181  CDIYIWAPLA GTCGVLLLSL VITLYCNHRN RRRVCKCPRP VVKSGDKPSL SARYV

LocalizationUniProt · AlphaFold · HPA

Whether an antibody against CD8A 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

1

Mean surface accessibility (rSASA)

0.48

Highest tissue expression

216 nTPM

Expression across tissuesHPA

DiseaseUniProt · ClinVar · IEDB · PubMed

Four sources answering four different questions about CD8A.

Disease | AllUniProt

Conditions CD8A is implicated in, by any mechanism.

• Immunodeficiency 116 (IMD116) MIM:608957

Disease | GeneticClinVar

2 pathogenic / likely-pathogenic of 218 ClinVar records.

Conditions with pathogenic or likely-pathogenic variants.

• Susceptibility to respiratory infections associated with CD8alpha chain mutation

Disease | AutoantibodyPubMed

Conditions in which antibodies against CD8A are reported. Each links to that disease's full target list.

• Diabetes Mellitus, Type 1 3
• Encephalomyelitis, Autoimmune, Experimental 3
• Proteinuria 3

ReferencesPubMed · IEDB

Publications for CD8A from three distinct lines of evidence, kept separate because they answer different questions: whether antibodies are directed at the protein, whether a B-cell epitope has been mapped on it, and whether a T-cell epitope has. Each is labelled with its source.

Sources: PubMed — antigen-level antibody evidence from a custom retrieval. Records matching a controlled set of autoantibody terms (the MeSH descriptors Autoantibodies and Autoantigens, with title and abstract term variants) were obtained through NCBI E-utilities, and their titles and abstracts parsed for constructions that direct an antibody at a named protein rather than for co-occurrence. Captured names were resolved against UniProt nomenclature and each antigen adjudicated individually against the source text. Bibliographic records from PubMed and MeSH, U.S. National Library of Medicine; citation metrics from NIH iCite (Hutchins et al., PLoS Biology 2016). Titles link to PubMed; abstracts are not reproduced here. The NLM does not endorse this analysis.

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)

1.5

gnomAD pLI

0

gnomAD missense Z

0.24

DepMap mean gene effect

-0.03

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

• adaptive immune response
• antigen processing and presentation
• cell surface receptor protein tyrosine kinase signaling pathway
• cell surface receptor signaling pathway
• immune response
• T cell activation
• T cell mediated immunity
• T cell receptor signaling pathway
• cytotoxic T cell differentiation

Molecular functions

• coreceptor activity
• MHC class I protein binding
• MHC class I protein complex binding

Cellular components

• external side of plasma membrane
• extracellular region
• plasma membrane
• plasma membrane raft
• receptor complex
• T cell receptor complex

Protein domainsUniProt · Pfam · InterPro

• Immunoglobulin domain subtype
• Immunoglobulin-like domain
• Immunoglobulin V-set domain
• Immunoglobulin-like fold
• Immunoglobulin-like domain superfamily
• Immunoglobulin V-set domain
• CD8 alpha subunit

KeywordsUniProt

• Adaptive immunity
• Cell membrane
• Disulfide bond
• Glycoprotein
• Immunity
• Immunoglobulin domain
• Lipoprotein
• Membrane
• Palmitate
• Secreted
• Signal
• Transmembrane
• Transmembrane helix

InteractionsUniProt · HPA

Protein binding partners of CD8A in the human serome: UniProt-annotated complex subunits plus reported interactors. Each links to its own Seroatlas record.

• HLA-G
• LCK