The Vif protein of human immunodeficiency virus type 1 is posttranslationally modified by ubiquitin

Regulation of Apobec3F and Human Immunodeficiency Virus Type 1 Vif by Vif-Cul5-ElonB/C E3 Ubiquitin Ligase

“…We and others have previously shown that HIV-1 Vif itself is also a target of proteasome-mediated degradation (10,20,26). While Vif has been shown to be both monoubiquitinated and polyubiquitinated, the mechanism of its regulation is still unclear (8,27). We observed that the stability of HIV-1 Vif was higher in the presence of Cul5⌬Nedd8 (Fig.…”

“…This observation raises the question of whether Vif is also the target of other E3 ubiquitin ligases. Interaction of HIV-1 Vif with other E3 ligases, such as Nedd4, AIP4 (8), and Zin (9) has been reported, but whether these proteins contribute to HIV-1 Vif degradation remains an open question.…”

APOBEC3G Ubiquitination by Nedd4-1 Favors its Packaging into HIV-1 Particles

“…Cell extracts and GST derivatives were incubated together in order to perform the in vitro protein-protein interactions as previously described. 25 VLP production assay At 24 hours after infection by vaccinia virus and transfection of HeLa cells with plasmids expressing the Gag gene, 2 ml of culture supernatant were collected from each well (containing 5!10 5 cells). After clarification by low-speed centrifugation at 4 8C to remove the nonadherent cells, the VLP were concentrated by centrifugation through a 20% sucrose cushion at 70,000 rpm in a TL100 Beckman rotor for 25 minutes at 4 8C.…”

Role of the single deaminase domain APOBEC3A in virus restriction, retrotransposition, DNA damage and cancer

“…Vif accomplishes this by binding to hA3G and CBF-b, an allosteric regulator of Vif. Vif then recruits the E3 ubiquitin ligase composed of Cullin 5, Elongin B, Elongin C and ring box subunit 2 (RBX2), resulting in the polyubiquitination of hA3G and targeting the complex to the proteasome for destruction (Conticello et al, 2003;Marin et al, 2003;Sheehy et al, 2003;Stopak et al, 2003;Dussart et al, 2004;Liu et al, 2004;Mehle et al, 2004b;Yu et al, 2004;Kobayashi et al, 2005;Zhang et al., 2011;Jäger et al, 2012). In terms of virus maturation, the end result of Vif-mediated ubiquitination and degradation of hA3G is that hA3G is not incorporated (or not to any meaningful extent) into budding virions.…”