CD8 alpha-beta T-cell surface glycoprotein (CD8αβ)

The CD8 alpha-beta T-cell surface glycoprotein (CD8αβ) is a transmembrane heterodimeric co-receptor expressed primarily on cytotoxic CD8+ αβ T cells, consisting of CD8α and CD8β chains each with an extracellular IgV-like domain, flexible hinge, transmembrane domain, and cytoplasmic tail. It binds the α3 domain of MHC class I molecules to enhance T-cell receptor (TCR) affinity during antigen recognition, recruits Lck kinase via a zinc-stabilized interaction in the CD8α cytoplasmic tail to initiate TCR signaling through CD3 ITAM phosphorylation, localizes to lipid rafts for immunological synapse formation, and supports T-cell development including thymocyte selection and maturation into memory subsets. CD8αβ acts as a stronger co-stimulator than CD8αα homodimers due to better Lck recruitment, with structural features like conserved Ig folds, disulfide bonds, O-linked glycosylation in the hinge, and palmitoylation aiding function.

Other names

CD8 co-receptorCD8αβ heterodimerCD8 glycoprotein

Blockade of CD8/MHC-I interaction, Modulation of T-cell activation, Promotion or abrogation of TCR signaling, Engineering into CAR T-cell hinges and transmembrane domains