title: HIV-1 Vpr Abrogates the Effect of TSG101 Overexpression to Support Virus Release.
abstract: HIV-1 budding requires interaction between Gag and cellular TSG101 to initiate viral particle assembly and release via the endosomal sorting complexes required for transport (ESCRT) pathway. However, some reports show that overexpression of TSG101 inhibits virus release by disruption of Gag targeting process. Since a HIV-1 accessory protein, Vpr binds to Gag p6 domain at the position close to the binding site for TSG101, whether Vpr implicates TSG101 overexpression effect has not been investigated. Here, we found that Vpr abrogates TSG101 overexpression effect to rescue viral production. Co-transfection of TSG101 and Gag with Vpr prevented TSG101-induced Gag accumulation in endosomes and lysosomes. In addition, Vpr rescued virus-like particle (VLP) production in a similar manner as a lysosomal inhibitor, Bafilomycin A1 indicating that Vpr inhibits TSG101-induced Gag downregulation via lysosomal pathway. Vpr and Gag interaction is required to counteract TSG101 overexpression effect since Vpr A30F mutant which is unable to interact with Gag and incorporate into virions, reduced ability to prevent Gag accumulation and to rescue VLP production. In addition, GST pull-down assays and Biacore analysis revealed that Vpr competed with TSG101 for Gag binding. These results indicate that Vpr overcomes the effects of TSG101 overexpression to support viral production by competing with TSG101 to bind Gag.
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, Japan.|Japan Foundation for AIDS Prevention, Chiyoda-ku, Tokyo, Japan.
authors.forename: Nopporn
authors.initials: N
authors.lastname: Chutiwitoonchai
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, Japan.|Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo, Tokyo, Japan.
authors.forename: Lowela
authors.initials: L
authors.lastname: Siarot
authors.affiliation: Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Takeda
authors.affiliation: Research Institute for Microbial Diseases, Osaka University, Suita, Osaka, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Shioda
authors.affiliation: Nano Medical Engineering Laboratory, RIKEN, Wako, Saitama, Japan.
authors.forename: Motoki
authors.initials: M
authors.lastname: Ueda
authors.affiliation: Viral Infectious Diseases Unit, RIKEN, Wako, Saitama, Japan.
authors.forename: Yoko
authors.initials: Y
authors.lastname: Aida
mesh_terms: D015153:Blotting, Western; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D015683:Gene Products, gag / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D008856:Microscopy, Fluorescence / Q000379:methods; D009154:Mutation; D011485:Protein Binding; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D019065:Virus Assembly / Q000235:genetics; D057074:Virus Release / Q000235:genetics / Q000502:physiology*; D054325:vpr Gene Products, Human Immunodeficiency Virus / Q000235:genetics / Q000378:metabolism*; D000099177:Tsg101 Protein
chemical_list: D004268:DNA-Binding Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D015683:Gene Products, gag; D014157:Transcription Factors; D054325:vpr Gene Products, Human Immunodeficiency Virus; D000099177:Tsg101 Protein; C514912:vpr protein, Human immunodeficiency virus 1