Abstract:
FasL mediated preferential apoptosis of bystander CTLs while protection of infected CD4+T cells remains one of the hallmarks of immune evasion during HIV infection. The property of infected host
cells to evade cell-autonomous apoptosis emanates from ability of HIV-1Nef -protein to physically interact with ASK-1 and thereby inhibit its enzymatic activity. The specific domains of HIV-1Nef through which it may interact with ASK1 and thereby impair the ASK1 activity remain unidentified so
far and represent a major challenge towards developing clear understanding about the dynamics of this interaction. Using mammalian two hybrid screen in association with site directed mutagenesis and
competitive inhibitor peptides, we identified constituent minimal essential domain (152 DEVGEANN 159) through which HIV-1Nef interacts with ASK1 and inhibits its function. Furthermore our study also unravels a novel alternate mechanism underlying HIV-1 Nef mediated ASK1 functional modulation,
wherein by potentiating the inhibitory ser967 phosphorylation of ASK1, HIV-1Nef negatively modulated ASK1function.
