Different fusion precursors respond differentially to indinavir inhibition. All fusion precursors were derived from the GST-p6*-PR-HA construct. Differences in the PR region are listed on the top. Precursor autoprocessing in transfected HEK293T cells was examined in the presence of increasing indinavir concentrations. Post-nuclear cell lysates were prepared at 30 h post transfection and subjected to western blot analysis. Each sample was probed using mouse anti-Flag (top) or anti-HA (bottom) primary antibodies in parallel. Open triangles indicate the apparent IC50 for the embedded protease. Asterisks denote self degradation IC50 of the released PR-HA and p6*-PR-HA. The products released by the cleavage reaction at the D site are connected by a dotted line and those at the P site by a solid line.