Vif hijacks CBF-β to degrade APOBEC3G and promote HIV-1 infection.

Restriction factors, such as the retroviral complementary DNA deaminase APOBEC3G, are cellular proteins that dominantly block virus replication. The AIDS virus, human immunodeficiency virus type 1 (HIV-1), produces the accessory factor Vif, which counteracts the host's antiviral defence by hijacking a ubiquitin ligase complex, containing CUL5, ELOC, ELOB and a ...
RING-box protein, and targeting APOBEC3G for degradation. Here we reveal, using an affinity tag/purification mass spectrometry approach, that Vif additionally recruits the transcription cofactor CBF-β to this ubiquitin ligase complex. CBF-β, which normally functions in concert with RUNX DNA binding proteins, allows the reconstitution of a recombinant six-protein assembly that elicits specific polyubiquitination activity with APOBEC3G, but not the related deaminase APOBEC3A. Using RNA knockdown and genetic complementation studies, we also demonstrate that CBF-β is required for Vif-mediated degradation of APOBEC3G and therefore for preserving HIV-1 infectivity. Finally, simian immunodeficiency virus (SIV) Vif also binds to and requires CBF-β to degrade rhesus macaque APOBEC3G, indicating functional conservation. Methods of disrupting the CBF-β-Vif interaction might enable HIV-1 restriction and provide a supplement to current antiviral therapies that primarily target viral proteins.
Mesh Terms:
Affinity Labels, Animals, Core Binding Factor beta Subunit, Cullin Proteins, Cytidine Deaminase, Gene Knockdown Techniques, Gene Products, vif, Genetic Complementation Test, HEK293 Cells, HIV Infections, HIV-1, Host-Pathogen Interactions, Humans, Jurkat Cells, Macaca mulatta, Mass Spectrometry, Models, Biological, Protein Binding, Proteolysis, Simian immunodeficiency virus, Ubiquitin-Protein Ligases, Ubiquitination, Virus Replication, vif Gene Products, Human Immunodeficiency Virus
Nature
Date: Jan. 19, 2012
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