FIG. 5.

Proteolytic cleavage of Pr55^gag in transfected COS-1 cell membranes. COS-1 cells were transfected with pHXB2gtpΔBal-D25S, and the plasma membrane-enriched fraction was isolated as described in Materials and Methods. Membranes were incubated (+ PR) or not incubated (− PR) with HIV-1 protease in the presence of 0.1% Triton X-100. The reactions were performed in the absence of salt addition or with 0.5 M NaCl added during or immediately after (last two lanes) proteolysis. The products were fractionated into soluble (S) and membrane bound (P) and resolved by SDS gel electrophoresis. p17MA was visualized by Western blotting (WB) with anti-p17MA monoclonal antibody (bottom panel). The blot was stripped and reprobed with anti-p24CA antibody to detect Pr55^gag and p24CA (top panel).