title: In vitro binding and phosphorylation of human immunodeficiency virus type 1 Nef protein by serine/threonine protein kinase.
abstract: Although the human immunodeficiency virus type 1 (HIV-1) nef gene still has no precisely defined function, in vivo studies have demonstrated that Nef is an important pathogenic determinant of HIV. In order to identify cellular proteins capable of binding to Nef, the HIV-1LAI nef gene product was expressed in the bacterial vector pGEX-2T as a glutathione S-transferase (GST)-Nef fusion protein. Deletion mutants corresponding to 86 and 35 N-terminal residues of the Nef protein were prepared. The GST-Nef constructs were used to identify cellular kinases capable of interacting with Nef. After incubation with a Jurkat cell lysate, the GST-Nef constructs immobilized on glutathione-agarose beads bound to cellular kinase(s) and were phosphorylated at three sites in vitro: one on threonine at position 15, one on serine between residues 1 and 35, and one on threonine between residues 36 and 86. The Nef-phosphorylating activity was inhibited by protein kinase C (PKC)-selective inhibitors. Cell fractionation showed that this Nef-binding kinase was mainly in the membrane-associated fraction. These results suggest that kinase(s) of the PKC family are specifically bound to and phosphorylate Nef in vitro. The interaction of Nef with cellular kinases and its phosphorylation may be important in mediating the effects of Nef in HIV-1 pathogenesis.
authors.affiliation: INSERM U332, Institut Cochin de Génétique Moléculaire, Université Paris V-René Descartes, France.
authors.forename: M
authors.initials: M
authors.lastname: Bodéus
authors.forename: A
authors.initials: A
authors.lastname: Marie-Cardine
authors.forename: C
authors.initials: C
authors.lastname: Bougeret
authors.forename: F
authors.initials: F
authors.lastname: Ramos-Morales
authors.forename: R
authors.initials: R
authors.lastname: Benarous
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D017931:DNA Primers; D015693:Gene Products, nef / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D015754:Genes, nef; D005982:Glutathione Transferase / Q000096:biosynthesis / Q000378:metabolism; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010768:Phosphoserine / Q000032:analysis; D010769:Phosphothreonine / Q000032:analysis; D019000:Phosphotyrosine; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D017384:Sequence Deletion; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis; D054311:nef Gene Products, Human Immunodeficiency Virus
chemical_list: D017931:DNA Primers; D015693:Gene Products, nef; D011993:Recombinant Fusion Proteins; D054311:nef Gene Products, Human Immunodeficiency Virus; D010769:Phosphothreonine; D010768:Phosphoserine; D019000:Phosphotyrosine; D014443:Tyrosine; D005982:Glutathione Transferase; D017346:Protein Serine-Threonine Kinases