Proteolytic cleavage sites of LEDGF/p75 by HIV-1 protease (PR). Recombinant LEDGF/p75 proteolysis by HIV-1 PR over a period of 2 hours by (A) Coomassie staining after SDS-PAGE and by (B) immunoblotting using anti-LEDGF/p75 antibody (A300-848A). (C) Addition of Ritonavir (RTV) inhibits Flag-LEDGF/p75 proteolysis by HIV-1 protease in a concentration dependent manner as shown by Coomassie staining. (D) Schematic representation of full length LEDGF/p75, HIV-1 PR cleavage sites confirmed by N-terminal protein sequencing (red arrow-heads) and the resulting fragments. The antibody epitope is marked. Coomassie stained gel of LEDGF/p75 cleavage products with the indicated molecular mass calculated based on their relative mobility (estimated weight) . Arrowheads indicate bands representing BSA (grey), LEDGF/p75 full length (black) and HIV PR (open arrowheads) in A, C and D.