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

PLoS Pathogens

Julien R. C. Bergeron¹  Dennis A. Veselkov¹  Mark R. Sanderson¹  Michael H. Malim²  Stephen J. Matthews²  Rebecca L. Beavil³  Hendrik Huthoff³  Peter J. Simpson³ 

[1] Department of Infectious Diseases, King's College London School of Medicine, London, United Kingdom;Division of Molecular Biosciences, Imperial College London, London, United Kingdom;Randall Division of Cell and Molecular Biophysics, King's College London, London, United Kingdom

关键词: HIV-1;    NMR spectroscopy;    Sequence motif analysis;    Crystal structure;    Protein interactions;    Ubiquitin ligases;    Binding analysis;    Co-immunoprecipitation;   

DOI  :  10.1371/journal.ppat.1000925

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The HIV-1 viral infectivity factor (Vif) protein recruits an E3 ubiquitin ligase complex, comprising the cellular proteins elongin B and C (EloBC), cullin 5 (Cul5) and RING-box 2 (Rbx2), to the anti-viral proteins APOBEC3G (A3G) and APOBEC3F (A3F) and induces their polyubiquitination and proteasomal degradation. In this study, we used purified proteins and direct in vitro binding assays, isothermal titration calorimetry and NMR spectroscopy to describe the molecular mechanism for assembly of the Vif-EloBC ternary complex. We demonstrate that Vif binds to EloBC in two locations, and that both interactions induce structural changes in the SOCS box of Vif as well as EloBC. In particular, in addition to the previously established binding of Vif's BC box to EloC, we report a novel interaction between the conserved Pro-Pro-Leu-Pro motif of Vif and the C-terminal domain of EloB. Using cell-based assays, we further show that this interaction is necessary for the formation of a functional ligase complex, thus establishing a role of this motif. We conclude that HIV-1 Vif engages EloBC via an induced-folding mechanism that does not require additional co-factors, and speculate that these features distinguish Vif from other EloBC specificity factors such as cellular SOCS proteins, and may enhance the prospects of obtaining therapeutic inhibitors of Vif function.

【 授权许可】

CC BY