gp41 & CD3

gp41/120 is the major HIV protein associated with the HIV envelope. It functions as the viral antireceptor or attachment protein. gp41 (or TM) traverses the envelope, whereas gp120 is present on the outer surface and is noncovalently attached to gp41. The precursor of gp120/41 (gp160) is synthesized in the endoplasmic reticulum and is transported via the golgi body to the cell surface. Upon activation of the envelope glycoprotein (gp120/41) by cellular receptors, gp41 undergoes conformational changes that mediate fusion of the viral and cellular membranes.

In immunology, the CD3 (cluster of differentiation 3) T-cell co-receptor is a protein complex and is composed of four distinct chains. In mammals, the complex contains a CD3γ chain, a CD3δ chain, and two CD3ε chains. These chains associate with a molecule known as the T-cell receptor (TCR) and the ζ-chain to generate an activation signal in T lymphocytes. The TCR, ζ-chain, and CD3 molecules together comprise the TCR complex.