The extracellular processing of HIV-1 envelope glycoprotein gp160 by humanplasmin

Cleavage of the envelope glycoprotein precursor gp160 of HIV-1 is a prerequ isite for the infectivity of HIV-1, and occurs at least in part before gp16 0 reaches the cell surface. Kexin/subtilisin-related endopeptidases are pro posed enzyme candidates for this intracellular processing. In this study. w e reveal the possibility that plasminogen hinds to the cell surface and par t of gp160 escaping intracellular processing is cleared by plasmin extracel lularly. Plasmin cleaves gp160 precisely at the C-terminal arginine residue of gp120, and the processing is effectively inhibited by an analogue pepti de of the cleavage motif (RXK/RR) and by plasmin inhibitors. (C) 1999 Feder ation of European Biochemical Societies.