title: GCN2 has inhibitory effect on human immunodeficiency virus-1 protein synthesis and is cleaved upon viral infection.
abstract: The reversible phosphorylation of the alpha-subunit of eukaryotic translation initiation factor 2 (eIF2alpha) is a well-characterized mechanism of translational control in response to a wide variety of cellular stresses, including viral infection. Beside PKR, the eIF2alpha kinase GCN2 participates in the cellular response against viral infection by RNA viruses with central nervous system tropism. PKR has also been involved in the antiviral response against HIV-1, although this antiviral effect is very limited due to the distinct mechanisms evolved by the virus to counteract PKR action. Here we report that infection of human cells with HIV-1 conveys the proteolytic cleavage of GCN2 and that purified HIV-1 and HIV-2 proteases produce direct proteolysis of GCN2 in vitro, abrogating the activation of GCN2 by HIV-1 RNA. Transfection of distinct cell lines with a plasmid encoding an HIV-1 cDNA clone competent for a single round of replication resulted in the activation of GCN2 and the subsequent eIF2alpha phosphorylation. Moreover, transfection of GCN2 knockout cells or cells with low levels of phosphorylated eIF2alpha with the same HIV-1 cDNA clone resulted in a marked increase of HIV-1 protein synthesis. Also, the over-expression of GCN2 in cells led to a diminished viral protein synthesis. These findings suggest that viral RNA produced during HIV-1 infection activates GCN2 leading to inhibition of viral RNA translation, and that HIV-1 protease cleaves GCN2 to overcome its antiviral effect.
authors.affiliation: Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: del Pino
authors.forename: José Luis
authors.initials: JL
authors.lastname: Jiménez
authors.forename: Iván
authors.initials: I
authors.lastname: Ventoso
authors.forename: Alfredo
authors.initials: A
authors.lastname: Castelló
authors.forename: Ma Ángeles
authors.initials: MÁ
authors.lastname: Muñoz-Fernández
authors.forename: César
authors.initials: C
authors.lastname: de Haro
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Berlanga
mesh_terms: D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity*; D006367:HeLa Cells; D006801:Humans; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D014764:Viral Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D015852:Eukaryotic Initiation Factor-2; D012367:RNA, Viral; D014764:Viral Proteins; C529271:EIF2AK4 protein, human; D017346:Protein Serine-Threonine Kinases