The SOCS-Box of HIV-1 Vif Interacts with ElonginBC by Induced-Folding to Recruit Its Cul5-Containing Ubiquitin Ligase Complex

The APOBEC3 deoxycytidine deaminases can restrict the replication of HIV-1 in cell culture to differing degrees. The effects of APOBEC3 enzymes are largely suppressed by HIV-1 Vif that interacts with host proteins to form a Cullin5-Ring E3 ubiquitin ligase that induces 48 K-linked polyubiquitination (poly-Ub) and proteasomal degradation of APOBEC3 enzymes. Vif variants have differing abilities to induce degradation of APOBEC3 enzymes and the underlying biochemical mechanisms for these differences is not fully understood. We hypothesized that by characterizing the interaction of multiple APOBEC3 enzymes and Vif variants we could identify common features that resulted in Vif-mediated degradation and further define the determinants required for efficient Vif-mediated degradation of APOBEC3 enzymes. We used Vifs from HIV-1 NL4-3 (IIIB) and HXB2 to characterize their induced degradation of and interaction with APOBEC3G, APOBEC3G D128K, APOBEC3H, and APOBEC3B in 293T cells. We quantified the APOBEC3G-Vif and APOBEC3H-Vif interaction strengths in vitro using rotational anisotropy.

mentioning

confidence: 99%

Determinants of Efficient Degradation of APOBEC3 Restriction Factors by HIV-1 Vif

Baig

Feng

Chelico

2014

“…Concerning Vif, the oligomerization sequence has been mapped between residues 151 and 164 in the C-terminal domain and more specifically to the 161 PPLP 164 motif (37,38,45). The PPLP motif was found to be required for the assembly of an active E3 ubiquitin ligase complex (43,44), and mutation of this sequence or the use of antagonist peptides has been shown to result in an important loss of viral infectivity (57), one of the reasons being an increased incorporation of A3G into viral particles as a consequence of the inhibition of its degradation (37,40,41,57).…”

Section: Discussionmentioning

confidence: 99%

“…This short domain was found to be crucial for Vif function and viral infectivity (37)(38)(39). Moreover, it can interact with A3G (40,41), cullin 5 (42), and the HIV-1 reverse transcriptase (35), and it was also observed that an intact PPLP motif is required for interaction between Vif and elongin B (43,44). Considering the involvement of the PPLP motif in Vif oligomerization, it is conceivable that all of these binding functions could be linked to the multimerization state of Vif.…”

mentioning

confidence: 99%

APOBEC3G Impairs the Multimerization of the HIV-1 Vif Protein in Living Cells

Batisse

Guerrero

Bernacchi

et al. 2013

Gag , Vif is largely relocated to the cell membrane, where Vif oligomerization also occurs. Interestingly, wild-type A3G strongly interferes with Vif multimerization, contrary to an A3G mutant that does not bind to Vif. These findings confirm that Vif oligomerization occurs in living cells partly through its C-terminal motif and suggest that A3G may target and perturb the Vif oligomerization state to limit its functions in the cell.

“…Long-range electrostatic interactions were calculated using the particle mesh Ewald (PME) method. The Berendsen thermostat was applied using a coupling time of 0.1 ps to maintain the system at a constant temperature of 300 K, and the pressure was also maintained by coupling to a reference pressure of 10 5 Pa by a Berendsen thermostat. The complex simulation began with 5,000-step energy minimization with conjugate gradient algorithm.…”

Section: Hiv-1 Infection Of Human T Cell Linesmentioning

confidence: 99%

Small-Molecule Inhibition of Human Immunodeficiency Virus Type 1 Replication by Targeting the Interaction between Vif and ElonginC

Zuo

Liu

et al. 2012

The HIV-1 viral infectivity factor (Vif) protein is essential for viral replication. Vif recruits cellular ElonginB/C-Cullin5 E3 ubiquitin ligase to target the host antiviral protein APOBEC3G (A3G) for proteasomal degradation. In the absence of Vif, A3G is packaged into budding HIV-1 virions and introduces multiple mutations in the newly synthesized minus-strand viral DNA to restrict virus replication. Thus, the A3G-Vif-E3 complex represents an attractive target for development of novel anti-HIV drugs. In this study, we identified a potent small molecular compound (VEC-5) by virtual screening and validated its anti-Vif activity through biochemical analysis. We show that VEC-5 inhibits virus replication only in A3G-positive cells. Treatment with VEC-5 increased cellular A3G levels when Vif was coexpressed and enhanced A3G incorporation into HIV-1 virions to reduce viral infectivity. Coimmunoprecipitation and computational analysis further attributed the anti-Vif activity of VEC-5 to the inhibition of Vif from direct binding to the ElonginC protein. These findings support the notion that suppressing Vif function can liberate A3G to carry out its antiviral activity and demonstrate that regulation of the Vif-ElonginC interaction is a novel target for small-molecule inhibitors of HIV-1.