title: Ubiquitination of APOBEC3G by an HIV-1 Vif-Cullin5-Elongin B-Elongin C complex is essential for Vif function.
abstract: The human immunodeficiency virus type 1 (HIV-1) virion infectivity factor (Vif) overcomes the antiviral activity of APOBEC3G to protect HIV-1 DNA from G-to-A hypermutation. Vif targets APOBEC3G for ubiquitination and proteasomal degradation by forming an SCF-like E3 ubiquitin ligase complex composed of Cullin5, Elongin B, and Elongin C (Vif-BC-Cul5) through a novel SOCS-box motif. In this paper, we have established an in vitro ubiquitin conjugation assay with purified Vif-BC-Cul5 complex and reported that the Vif-BC-Cul5 complex could function as an E3 ligase for APOBEC3G in vitro. A Vif-BC-Cul5 complex promotes the in vitro ubiquitination of the wild type, APOBEC3G but not that of D128K mutant, which does not interact with Vif. We have also investigated several loss-of-function Vif mutants. One mutant, SLQ144/146AAA, lost its activity on APOBEC3G because it could not form a complex due to mutations in SOCS-box motif. Other mutants, C114S and C133S, also lost their activity because of loss of the E3 ligase activity of a Vif-BC-Cul5 complex, although these mutants retained the ability to bind to APOBEC3G as well as Cul5 complex. These findings suggest that the E3 ubiquitin ligase activity of the Vif-BC-Cul5 complex is essential for Vif function against APOBEC3G.
authors.affiliation: Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, 54 Shogoin-Kawaracho, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Akifumi
authors.initials: A
authors.lastname: Takaori-Kondo
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Miyauchi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Iwai
authors.forename: Takashi
authors.initials: T
authors.lastname: Uchiyama
mesh_terms: D000071480:APOBEC-3G Deaminase; D020816:Amino Acid Motifs; D000818:Animals; D016367:Baculoviridae / Q000378:metabolism; D002460:Cell Line; D044842:Cullin Proteins / Q000737:chemistry*; D003564:Cytidine Deaminase; D000075065:Elongin; D016346:Gene Products, vif / Q000737:chemistry*; D017930:Genes, Reporter; D005822:Genetic Vectors; D015497:HIV-1 / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D066298:In Vitro Techniques; D007313:Insecta; D008156:Luciferases / Q000378:metabolism; D009154:Mutation; D009700:Nucleoside Deaminases; D011485:Protein Binding; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D017483:Receptors, Vasopressin / Q000737:chemistry*; D011994:Recombinant Proteins / Q000737:chemistry; D012097:Repressor Proteins; D014157:Transcription Factors / Q000737:chemistry*; D025801:Ubiquitin / Q000737:chemistry* / Q000378:metabolism; D054320:vif Gene Products, Human Immunodeficiency Virus
chemical_list: C496871:CUL5 protein, human; D044842:Cullin Proteins; C000616396:ELOB protein, human; C000616395:ELOC protein, human; D000075065:Elongin; D016346:Gene Products, vif; D011506:Proteins; D017483:Receptors, Vasopressin; D011994:Recombinant Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D025801:Ubiquitin; D054320:vif Gene Products, Human Immunodeficiency Virus; D008156:Luciferases; D009700:Nucleoside Deaminases; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase