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Kogan M, Deshmane S, Sawaya BE, Gracely EJ, Khalili K, Rappaport J
Inhibition of NF-kappaB activity by HIV-1 Vpr is dependent on Vpr binding protein
J Cell Physiol (2013) 228:781-90.
Numerous studies have reported that Vpr alters NF-kappaB signaling in various cell types, however, the findings have been largely conflicting with reports of both stimulatory and inhibitory effects of Vpr. Our aim was to investigate the role of Vpr signaling in myeloid cells using an adenovirus based expression and indicator system. Our results show that Vpr is inhibitory to NF-kappaB, however, this effect is dependent on the particular manner of NF-kappaB stimulation. Consistent with this notion, we report that Vpr has inhibitory effects that are specific to the TNF-alpha pathway, but not affecting the LPS pathway, suggesting that differential targets of Vpr may exist for NF-kappaB regulation. Further, we identify VprBP as one possible cellular component of Vpr's regulation of IkappaBalpha in response to TNF-alpha stimulation. We did not identify such a role for HSP27, which instead seems to inhibit Vpr functions. Chronically HIV-1 infected U1 cells with knockdown constructs for Vpr were unexpectedly less responsive to TNF-alpha mediated viral replication, perhaps suggesting that other HIV-1 components may antagonize these anti-NF-kappaB effects in infected cells. We hypothesize that Vpr may serve an important role in the context of viral infection and immune function in vivo, through its selective inhibition of NF-kappaB pathways.
Publication Date: 2013-04-01.
PMCID: Pmc3604695
Last updated on Wednesday, March 04, 2020