Heat-Shock Proteins Reverse the G 2 Arrest Caused by HIV-1 Viral Protein R

Abstract

HIV-1 Vpr is an important contributor to viral pathogenesis. Vpr displays several highly conserved pathogenic activities, including induction of cell cycle G₂ arrest and cell death. The host immune system, in turn, preferentially targets Vpr in an attempt to reduce its pathogenic effects. To identify innate anti-Vpr factors, we performed a genetic search for multicopy suppressors of Vpr-induced G₂ arrest in fission yeast. Several heat-shock proteins were identified in these experiments. Analyses in mammalian cells demonstrated that heatshock proteins HSP27 and HSP70 suppress Vpr-induced G2 arrest. This effect appears to be mediated by an interaction between heat shock proteins and Vpr. These results illustrate another example of antagonistic interactions between the viral and cellular proteins.