FIG 8 .

Post-NPC1-binding cathepsin activity is required for infection but not EBOV GP triggering. (A) Immunoblot showing the extent of GP1 cleavage in three EBOV GPΔMuc-pseudotyped virus preparations. The asterisk indicates a cleavage intermediate of GP1. (B) The E-64d cysteine protease inhibitor (25 µM) completely blocks infection. (C) Precleaved EBOV GPΔMuc can induce lipid mixing in the absence of cathepsin activity (25 µM E-64d). Asterisks indicate that values are significantly lower than those seen with the untreated, uncleaved control.