HIV-1 Vif (viral infectivity factor) protein overcomes the antiviral activity of the DNA deaminase APOBEC3G by targeting it for proteasomal degradation. We report here that Vif targets APOBEC3G for degradation by forming an SCF-like E3 ubiquitin ligase containing Cullin 5 and Elongins B and C (Cul5-EloB-EloC) through a novel SOCS (suppressor of cytokine signaling)-box that binds EloC. Vif binding to EloC is negatively regulated by serine phosphorylation in the BC-box motif of the SOCS-box. Vif ubiquitination is promoted by Cul5 in vitro and in vivo, and requires an intact SOCS-box. Thus, autoubiquitination of Vif occurs within the assembled Vif-Cul5 complex, analogous to F-box proteins that are autoubiquitinated within their SCF (Skp1-Cullin-F-box) complex. These findings suggest mechanisms that regulate the assembly and activity of Cul5 E3 complexes through phosphorylation or autoubiquitination of the SOCS-box protein, and identify interactions between Vif and host cell proteins that may be therapeutic targets.
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http://dx.doi.org/10.1101/gad.1249904 | DOI Listing |
Virology
February 2021
Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany. Electronic address:
The family of human APOBEC3 (A3) restriction factors is formed by seven different proteins, A3A-D and A3F-H. Among these A3s, A3B harbors strong restriction activity against several retroviruses, such as SIV, and MLV. How lentiviruses and other retroviruses, prevalent in many primate species, counteract A3B is poorly understood.
View Article and Find Full Text PDFBiochem Biophys Res Commun
April 2019
Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, Jilin, 130061, China; Cancer Institute (Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education), Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310009, China. Electronic address:
Interaction between HIV-1 Vif and host factor CBFβ leads to the assembly of the Vif-Cul5-EloB/C ubiquitin ligase (E3 complex). By inducing the formation of E3 complex, Vif depletes host APOBEC3 restriction factors and promotes HIV-1 infection. In addition, Vif is known to arrest host cells at G2/M phase (G2 arrest), benefiting HIV-1 replication and contributing to the depletion of CD4 T cells.
View Article and Find Full Text PDFJ Virol
March 2018
Clinic for Gastroenterology, Hepatology, and Infectiology, Medical Faculty, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
Members of the apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like (APOBEC3 [A3]) family of DNA cytidine deaminases are intrinsic restriction factors against retroviruses. In felids such as the domestic cat (), the A3 genes encode the A3Z2, A3Z3, and A3Z2Z3 antiviral cytidine deaminases. Only A3Z3 and A3Z2Z3 inhibit viral infectivity factor (Vif)-deficient feline immunodeficiency virus (FIV).
View Article and Find Full Text PDFBiochem Biophys Res Commun
June 2015
National Engineering Laboratory for AIDS Vaccine, College of Life Science, Jilin University, Changchun, Jilin Province, People's Republic of China; Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education, College of Life Science, Jilin University, Changchun, Jilin Province, People's Republic of China. Electronic address:
Rbx1 and Rbx2 are essential components of Cullin-RING E3 Ligases. Vif is generally believed to preferentially recruit the Cul5-Rbx2 module to induce proteasomal degradation of antiretroviral enzyme APOBEC3G, although some investigators have found that the Cul5-Rbx1 module is recruited. Here, to investigate the function of the two Rbx proteins in the Vif-Cul5 complex, we analyzed the performance of Cul5-Rbx1/Cul5-Rbx2 module in the activity of Vif E3 ligase and evaluated the interactions between Rbx1/Rbx2 and Cul5.
View Article and Find Full Text PDFRetrovirology
January 2014
Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615 N, Wolfe Street, Baltimore, MD 21205, USA.
Background: HIV-1 Vif promotes the degradation of host anti-retroviral factor family, APOBEC3 proteins via the recruitment of a multi-subunit E3 ubiquitin ligase complex. The complex is composed of a scaffold protein, Cullin 5 (Cul5), RING-box protein (Rbx), a SOCS box binding protein complex, Elongins B/C (Elo B/C), as well as newly identified host co-factor, core binding factor beta (CBF-β). Cul5 has previously been shown to bind amino acids within an HCCH domain as well as a PPLP motif at the C-terminus of Vif; however, it is unclear whether Cul5 binding requires additional regions of the Vif polypeptide.
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