title: Novel (n)PKC kinases phosphorylate Nef for increased HIV transcription, replication and perinuclear targeting.
abstract: The N-terminus of the human immunodeficiency virus (HIV) pathogenicity factor Nef associates with a protein complex (NAKC for Nef-associated kinase complex) that contains at least two kinases: the tyrosine kinase Lck and a serine kinase activity which was found to phosphorylate Lck and the Nef N-terminus. Here we show that this serine kinase activity is mediated by members of the novel Protein Kinase C (nPKC) subfamily, PKCdelta and theta. Association with the Nef N-terminus was sufficient to activate PKC leading to phosphorylation of Nef in vitro on a conserved serine residue at position 6. Mutation of serine 6 or coexpression of a transdominant negative PKC mutant significantly reduced Nef-stimulated HIV transcription and replication in resting PBMC. When analyzing the molecular mechanisms, we found that mutating serine 6 moderately affected myristoylation of Nef and its association with Pak2 activity, whereas CD4 downmodulation was not inhibited. More interestingly, this mutation abolished the typical perinuclear localization of Nef in T cells. We conclude that the activation of nPKCs by Nef is required to increase viral replication/infectivity and direct the subcellular localization of Nef.
authors: University of Miami, Miller School of Medicine, Department of Microbiology and Immunology, BCRI 739, Miami, FL 33136, USA.
authors: Dietlinde
authors: D
authors: Wolf
authors: Simone I
authors: SI
authors: Giese
authors: Vanessa
authors: V
authors: Witte
authors: Ellen
authors: E
authors: Krautkrämer
authors: Susanna
authors: S
authors: Trapp
authors: Gabriele
authors: G
authors: Sass
authors: Claudia
authors: C
authors: Haller
authors: Katja
authors: K
authors: Blume
authors: Oliver T
authors: OT
authors: Fackler
authors: Andreas S
authors: AS
authors: Baur
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D015754:Genes, nef; D015497:HIV-1 / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D019169:Jurkat Cells; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051745:Protein Kinase C-delta / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism*; D014158:Transcription, Genetic; D014779:Virus Replication; D054311:nef Gene Products, Human Immunodeficiency Virus / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D009097:Multienzyme Complexes; D054311:nef Gene Products, Human Immunodeficiency Virus; D011493:Protein Kinase C; D051745:Protein Kinase C-delta