CD8A
Function
The protein expressed by the gene CD8A is an integral membrane glycoprotein crucial for immune responses, operating mainly in T-cells as a coreceptor for MHC class I molecule:peptide complexes. These peptides originate from cytosolic proteins, unlike class II peptides, which are from extracellular proteins. CD8A interacts with the T-cell receptor (TCR) and MHC class I proteins on antigen-presenting cells, recruiting the Src kinase LCK to the TCR-CD3 complex. LCK phosphorylates substrates, triggering signaling pathways that lead to the production of lymphokines, enhanced motility, adhesion, and activation of cytotoxic T-lymphocytes (CTLs), thereby aiding in the recognition and elimination of infected or tumor cells. Additionally, in natural killer (NK) cells, CD8A homodimers on the cell surface provide a survival mechanism for conjugating with and lysing multiple target cells. CD8A homodimers also facilitate the survival and differentiation of activated lymphocytes into memory CD8 T-cells. This supplementary information is collated from multiple sources and compiled automatically.
Involvement in disease
Immunodeficiency 116
IMD116
An autosomal recessive immunologic defect characterized by absence of CD8+ cells, leading to recurrent bacterial infections.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
Palmitoylated, but association with CD8B seems to be more important for the enrichment of CD8A in lipid rafts.
O-glycosylated.
Phosphorylated in cytotoxic T-lymphocytes (CTLs) following activation.
Tissue Specificity
CD8 on thymus-derived T-cells usually consists of a disulfide-linked alpha/CD8A and a beta/CD8B chain. Less frequently, CD8 can be expressed as a CD8A homodimer. A subset of natural killer cells, memory T-cells, intraepithelial lymphocytes, monocytes and dendritic cells expresses CD8A homodimers. Expressed at the cell surface of plasmacytoid dendritic cells upon herpes simplex virus-1 stimulation.
Cellular localization
- Isoform 1
- Cell membrane
- Single-pass type I membrane protein
- CD8A localizes to lipid rafts only when associated with its partner CD8B.
- Isoform 2
- Secreted
Alternative names
CD8a, MAL, CD8A, T-cell surface glycoprotein CD8 alpha chain, T-lymphocyte differentiation antigen T8/Leu-2
Database links
swissprot:P01732 swissprot:P28907 omim:107270 omim:186730 omim:186760 omim:186910 swissprot:P10747 swissprot:P10966 entrezGene:940 entrezGene:952 entrezGene:926 entrezGene:925
Other research areas
- Immunology & Infectious Disease