CD4

Schematic representation of CD4 receptor. CD4 (cluster of differentiation 4) is a glycoprotein expressed on the surface of T helper cells, regulatory T cells, and dendritic cells. On T cells, CD4 is the co-receptor for the T cell receptor (TCR) and recruits the tyrosine kinase lck. With its D1-portion it attaches to the β2-domain of MHC class II molecules. CD4 is also a primary receptor for binding of HIV-1 through the gp120 envelope protein. This binding leads to a shift in the prote ...