In addition, evaluation of the cellular translation factors eIF4GI and PABP showed proteolytic processing when the HIV-1 protease was not inhibited. In contrast, evaluation of the inactive PR-D25N showed its inability to cleave eIF4GI and PABP (Figure 1d). Those results show that the pattern of resistance mutations within the HIV-1 protease and the concentration of the protease inhibitor are able to modulate the translation of cellular proteins, suggesting that our phenotypic system is based on the ability of HIV-1 protease to cleave cellular translation factors