HIV-1 Vpu does not degrade interferon regulatory factor 3.

It has been reported that HIV-1 Vpu mediates the degradation of interferon regulatory factor 3 (IRF-3) to avoid innate immune sensing. Here, we show that Vpu does not deplete IRF-3 from transfected cell lines or HIV-1-infected primary cells. Furthermore, the Vpu-dependent suppression of beta interferon expression described in previous studies could be ascribed to inhibition of NF-κB activation. Thus, Vpu suppresses innate immune activation through inhibition of NF-κB rather than degradation of IRF-3.