Dataset Information

Interactions between HIV-1 Vif and human ElonginB-ElonginC are important for CBF-? binding to Vif.

ABSTRACT: BACKGROUND: The HIV-1 accessory factor Vif is necessary for efficient viral infection in non-permissive cells. Vif antagonizes the antiviral activity of human cytidine deaminase APOBEC3 proteins that confer the non-permissive phenotype by tethering them (APOBEC3DE/3F/3G) to the Vif-CBF-?-ElonginB-ElonginC-Cullin5-Rbx (Vif-CBF-?-EloB-EloC-Cul5-Rbx) E3 complex to induce their proteasomal degradation. EloB and EloC were initially reported as positive regulatory subunits of the Elongin (SIII) complex. Thereafter, EloB and EloC were found to be components of Cul-E3 complexes, contributing to proteasomal degradation of specific substrates. CBF-? is a newly identified key regulator of Vif function, and more information is needed to further clarify its regulatory mechanism. Here, we comprehensively investigated the functions of EloB (together with EloC) in the Vif-CBF-?-Cul5 E3 ligase complex. RESULTS: The results revealed that: (1) EloB (and EloC) positively affected the recruitment of CBF-? to Vif. Both knockdown of endogenous EloB and over-expression of its mutant with a 34-residue deletion in the COOH-terminal tail (EloB?C34/EB?C34) impaired the Vif-CBF-? interaction. (2) Introduction of both the Vif SLQ ? AAA mutant (Vif?SLQ, which dramatically impairs Vif-EloB-EloC binding) and the Vif PPL ? AAA mutant (Vif?PPL, which is thought to reduce Vif-EloB binding) could reduce CBF-? binding. (3) EloB-EloC but not CBF-? could greatly enhance the folding of full-length Vif in Escherichia coli. (4) The over-expression of EloB or the N-terminal ubiquitin-like (UbL) domain of EloB could significantly improve the stability of Vif/Vif?SLQ/Vif?PPL through the region between residues 9 and 14. CONCLUSION: Our results indicate that the Vif interaction with EloB-EloC may contribute to recruitment of CBF-? to Vif, demonstrating that the EloB C-teminus may play a role in improving Vif function and that the over-expression of EloB results in Vif stabilization.

SUBMITTER: Wang X

PROVIDER: S-EPMC3765967 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Interactions between HIV-1 Vif and human ElonginB-ElonginC are important for CBF-β binding to Vif.

Wang Xiaodan X Wang Xiaoying X Zhang Haihong H Lv Mingyu M Zuo Tao T Wu Hui H Wang Jiawen J Liu Donglai D Wang Chu C Zhang Jingyao J Li Xu X Wu Jiaxin J Yu Bin B Kong Wei W Yu Xianghui X

Retrovirology 20130829

<h4>Background</h4>The HIV-1 accessory factor Vif is necessary for efficient viral infection in non-permissive cells. Vif antagonizes the antiviral activity of human cytidine deaminase APOBEC3 proteins that confer the non-permissive phenotype by tethering them (APOBEC3DE/3F/3G) to the Vif-CBF-β-ElonginB-ElonginC-Cullin5-Rbx (Vif-CBF-β-EloB-EloC-Cul5-Rbx) E3 complex to induce their proteasomal degradation. EloB and EloC were initially reported as positive regulatory subunits of the Elongin (SIII) ...[more]

PMID: 23988114

Similar Datasets

Project description:Several members of the APOBEC3 DNA cytosine deaminase family can potently inhibit Vif-deficient human immunodeficiency virus type 1 (HIV-1) by catalyzing cytosine deamination in viral cDNA and impeding reverse transcription. HIV-1 counteracts restriction with the virally encoded Vif protein, which targets relevant APOBEC3 proteins for proteasomal degradation. HIV-1 Vif is optimized for degrading the restrictive human APOBEC3 repertoire, and, in general, lentiviral Vif proteins specifically target the restricting APOBEC3 enzymes of each host species. However, simian immunodeficiency virus SIVmac239 Vif elicits a curiously wide range of APOBEC3 degradation capabilities that include degradation of several human APOBEC3s and even human APOBEC3B, a non-HIV-1-restricting APOBEC3 enzyme. To better understand the molecular determinants of the interaction between SIVmac239 Vif and human APOBEC3B, we analyzed an extensive series of mutants. We found that SIVmac239 Vif interacts with the N-terminal domain of human APOBEC3B and, interestingly, that this occurs within a structural region homologous to the HIV-1 Vif interaction surface of human APOBEC3G. An alanine scan of SIVmac239 Vif revealed several residues required for human APOBEC3B degradation activity. These residues overlap HIV-1 Vif surface residues that interact with human APOBEC3G and are distinct from those that engage APOBEC3F or APOBEC3H. Overall, these studies indicate that the molecular determinants of the functional interaction between human APOBEC3B and SIVmac239 Vif resemble those between human APOBEC3G and HIV-1 Vif. These studies contribute to the growing knowledge of the APOBEC-Vif interaction and may help guide future efforts to disrupt this interaction as an antiviral therapy or exploit the interaction as a novel strategy to inhibit APOBEC3B-dependent tumor evolution.IMPORTANCE Primate APOBEC3 proteins provide innate immunity against retroviruses such as HIV and SIV. HIV-1, the primary cause of AIDS, utilizes its Vif protein to specifically counteract restrictive human APOBEC3 enzymes. SIVmac239 Vif exhibits a much wider range of anti-APOBEC3 activities that includes several rhesus macaque enzymes and extends to multiple proteins in the human APOBEC3 repertoire, including APOBEC3B. Understanding the molecular determinants of the interaction between SIVmac239 Vif and human APOBEC3B adds to existing knowledge on the APOBEC3-Vif interaction and has potential to shed light on what processes may have shaped Vif functionality over evolutionary time. An intimate understanding of this interaction may also lead to a novel cancer therapy because, for instance, creating a derivative of SIVmac239 Vif that specifically targets human APOBEC3B could be used to suppress tumor genomic DNA mutagenesis by this enzyme, slow ongoing tumor evolution, and help prevent poor clinical outcomes.

Project description:Human APOBEC3H (A3H) is a cytidine deaminase that inhibits HIV-1 replication. To evade this restriction, the HIV-1 Vif protein binds A3H and mediates its proteasomal degradation. To date, little information on the Vif-A3H interface has been available. To decipher how both proteins interact, we first mapped the Vif-binding site on A3H by functionally testing a large set of A3H mutants in single-cycle infectivity and replication assays. Our data show that the two A3H ?-helixes ?3 and ?4 represent the Vif-binding site of A3H. We next used viral adaptation and a set of Vif mutants to identify novel, reciprocal Vif variants that rescued viral infectivity in the presence of two Vif-resistant A3H mutants. These A3H-Vif interaction points were used to generate the first A3H-Vif structure model, which revealed that the A3H helixes ?3 and ?4 interact with the Vif ?-sheet (?2-?5). This model is in good agreement with previously reported Vif and A3H amino acids important for interaction. Based on the predicted A3H-Vif interface, we tested additional points of contact, which validated our model. Moreover, these experiments showed that the A3H and A3G binding sites on HIV-1 Vif are largely distinct, with both host proteins interacting with Vif ?-strand 2. Taken together, this virus-host interface model explains previously reported data and will help to identify novel drug targets to combat HIV-1 infection.IMPORTANCE HIV-1 needs to overcome several intracellular restriction factors in order to replicate efficiently. The human APOBEC3 locus encodes seven proteins, of which A3D, A3F, A3G, and A3H restrict HIV-1. HIV encodes the Vif protein, which binds to the APOBEC3 proteins and leads to their proteasomal degradation. No HIV-1 Vif-APOBEC3 costructure exists to date despite extensive research. We and others previously generated HIV-1 Vif costructure models with A3G and A3F by mapping specific contact points between both proteins. Here, we applied a similar approach to HIV-1 Vif and A3H and successfully generated a Vif-A3H interaction model. Importantly, we find that the HIV-1 Vif-A3H interface is distinct from the Vif-A3G and Vif-A3F interfaces, with a small Vif region being important for recognition of both A3G and A3H. Our Vif-A3H structure model informs on how both proteins interact and could guide toward approaches to block the Vif-A3H interface to target HIV replication.

Dataset Information

Interactions between HIV-1 Vif and human ElonginB-ElonginC are important for CBF-? binding to Vif.

Publications

Interactions between HIV-1 Vif and human ElonginB-ElonginC are important for CBF-β binding to Vif.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets