title: Inhibition of cellular HIV-1 protease activity by lysyl-tRNA synthetase.
abstract: During early assembly of human immunodeficiency virus type 1 (HIV-1), an assembly complex is formed, the components of which include genomic RNA, Gag, GagPol, tRNA(Lys), and lysyl tRNA synthetase (LysRS). Directly increasing or decreasing cellular expression of LysRS results in corresponding changes in viral infectivity and in the viral concentrations of LysRS, tRNA(Lys), and, surprisingly, reverse transcriptase (RT). Since altering the cellular expression of LysRS does not lead to a change in the incorporation of the RT precursor protein, GagPol, in protease-negative HIV-1, we propose that the altered viral content of RT resulting from alterations in cellular LysRS concentration results from the ability of LysRS to inhibit premature activation of Gag-Pol viral protease within the complex. Supporting this hypothesis, we find that increases and decreases in cellular LysRS expression are accompanied by 5-8-fold increases and 5-fold decreases, respectively, in the cytoplasmic proteolysis of Gag and GagPol to mature viral proteins. Using a novel bioluminescence resonance energy transfer assay to directly measure HIV-1 protease activity in vivo also indicates that the overexpression of LysRS in the cell reduces viral protease activity.
authors.affiliation: Lady Davis Institute for Medical Research and McGill AIDS Centre, Jewish General Hospital, Montreal, Quebec H3T 1E2, Canada.
authors.forename: Fei
authors.initials: F
authors.lastname: Guo
authors.forename: Juliana
authors.initials: J
authors.lastname: Gabor
authors.forename: Shan
authors.initials: S
authors.lastname: Cen
authors.forename: Kimberly
authors.initials: K
authors.lastname: Hu
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Mouland
authors.forename: Lawrence
authors.initials: L
authors.lastname: Kleiman
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D003593:Cytoplasm / Q000378:metabolism; D004735:Energy Transfer; D015685:Fusion Proteins, gag-pol / Q000378:metabolism; D015683:Gene Products, gag / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D016333:HIV Protease / Q000378:metabolism*; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D054303:HIV Reverse Transcriptase / Q000378:metabolism; D006801:Humans; D008239:Lysine / Q000737:chemistry; D008250:Lysine-tRNA Ligase / Q000737:chemistry / Q000378:metabolism*; D010957:Plasmids / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D014162:Transfection; D014779:Virus Replication
chemical_list: D015685:Fusion Proteins, gag-pol; D015683:Gene Products, gag; D017320:HIV Protease Inhibitors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; D054303:HIV Reverse Transcriptase; D016333:HIV Protease; D008250:Lysine-tRNA Ligase; D008239:Lysine