Affiliation:
1. Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205
2. Harbin Veterinary Research Institute, CAAS, Harbin, China
3. Zhejiang University, Zhejiang, China
Abstract
ABSTRACT
The human cytidine deaminase Apobec3F (h-A3F), a protein related to the previously recognized antiviral factor Apobec3G (h-A3G), has antiviral activity against human immunodeficiency virus type 1 (HIV-1) that is suppressed by the viral protein Vif. The mechanism of HIV-1 Vif-mediated suppression of h-A3F is not fully understood. Here, we demonstrate that while h-A3F, like h-A3G, was able to suppress primate lentiviruses other than HIV-1 (simian immunodeficiency virus from African green monkeys [SIVagm] and Rhesus macaques [SIVmac]), the interaction between Vif proteins and h-A3F appeared to differ from that with h-A3G. H-A3F showed no change in its species specificity against HIV-1 or SIVagm Vif when a negatively charged amino acid was replaced with a lysine at position 128, a residue critical for h-A3G recognition by HIV-1 Vif. However, HIV-1 Vif, but not SIVagm Vif, was able to bind h-A3F and induce its polyubiquitination and degradation through the Cul5-containing E3 ubiquitin ligase. Interference with Cul5-E3 ligase function by depletion of Cul5, through RNA interference or overexpression of Cul5 mutants, blocked the ability of HIV-1 Vif to suppress h-A3F. A BC-box mutant of HIV-1 Vif that failed to recruit Cul5-E3 ligase but was still able to interact with h-A3F failed to suppress h-A3F. Interestingly, interference with Cul5-E3 ligase function or overexpression of h-A3F or h-A3G also increased the stability of HIV-1 Vif, suggesting that like the substrate molecules h-A3F and h-A3G, the substrate receptor protein Vif is itself also regulated by Cul5-E3 ligase. Our results indicate that Cul5-E3 ligase appears to be a common pathway hijacked by HIV-1 Vif to defeat both h-A3F and h-A3G. Developing inhibitors to disrupt the interaction between Vif and Cul5-E3 ligase could be therapeutically useful, allowing multiple host antiviral factors to suppress HIV-1.
Publisher
American Society for Microbiology
Subject
Virology,Insect Science,Immunology,Microbiology
Cited by
130 articles.
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