CD8A

T-cell surface glycoprotein CD8 alpha chain (Cluster of Differentiation 8a), is a protein encoded by CD8A gene.

Function
The CD8 protein is a cell surface glycoprotein found on most cytotoxic T lymphocytes that mediates efficient cell-cell interactions within the immune system. The CD8, acting as a coreceptor, and the T-cell receptor on the T lymphocyte recognize antigen displayed by an antigen-presenting cell (APC) in the context of class I MHC molecules. The functional coreceptor is either a homodimer composed of two alpha chains, or a heterodimer composed of one alpha and one beta chain. Both alpha and beta chains share significant homology to variable domain of immunoglobulin light chains. This gene encodes the CD8 alpha chain isoforms. Two alternative transcripts encoding distinct isoforms, one membrane associated and one secreted, have been identified.

Interactions
CD8A has been shown to interact with:
 * CD3D,
 * HLA-A, and
 * HLA-G.