The cytoplasmic tail of HIV-1 gp160 contains regions that associate with cellular membranes.

The HIV-1 envelope glycoprotein gp160 associates with cellular membranes via a discrete transmembrane domain. Unlike other retroviral envelope proteins, however, gp160 also forms a secondary association with the lipid bilayer mediated by one or more regions located in the cytoplasmic tail. We have expressed the full cytoplasmic tail sequence of gp160, as a fusion protein with the HSV-1 glycoprotein D signal sequence, transiently in a human embryonic kidney cell line. Our results show that in the absence of any defined transmembrane domain or stop transfer sequence, the protein corresponding to the cytoplasmic tail of HIV-1 gp160 formed stable interactions with cellular membranes that mediated its export to the cell surface.