title: Identification of three major phosphorylation sites within HIV-1 capsid. Role of phosphorylation during the early steps of infection.
abstract: We previously reported the presence of two cellular serine/threonine protein kinases incorporated in human immunodeficiency virus type 1 (HIV-1) particles. One protein kinase is MAPK ERK2 (mitogen-activated protein kinase), whereas the other one, a 53-kDa protein, still needs to be identified. Furthermore, we demonstrated that the capsid protein CAp24 is phosphorylated by one of those two virion-associated protein kinases (Cartier, C., Deckert, M., Grangeasse, C., Trauger, R., Jensen, F., Bernard, A., Cozzone, A., Desgranges, C., and Boyer, V. (1997) J. Virol. 71, 4832-4837). In this study, we showed that CAp24 is not a direct substrate of MAPK ERK2. Moreover, using site-directed mutagenesis of each of the 9 serine residues of CAp24, we demonstrated the phosphorylation of 3 serine residues (Ser-109, Ser-149, and Ser-178) in the CAp24. Substitution of each serine residue did not affect viral budding, nor viral structure. By contrast, substitution of Ser-109, Ser-149, or Ser-178 affects viral infectivity by preventing the reverse transcription process to be completely achieved. Our results suggest that CAp24 serine phosphorylation is essential for viral uncoating process.
authors.affiliation: Virus des Hépatites, Rétrovirus Humains et Pathologies Associées, INSERM U271, 151 Cours. A. Thomas, 69 424 Lyon Cedex 03, France. cartier@lyon151.inserm.fr
authors.forename: C
authors.initials: C
authors.lastname: Cartier
authors.forename: P
authors.initials: P
authors.lastname: Sivard
authors.forename: C
authors.initials: C
authors.lastname: Tranchat
authors.forename: D
authors.initials: D
authors.lastname: Decimo
authors.forename: C
authors.initials: C
authors.lastname: Desgranges
authors.forename: V
authors.initials: V
authors.lastname: Boyer
mesh_terms: D019943:Amino Acid Substitution; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002213:Capsid / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D004261:DNA Replication; D015658:HIV Infections / Q000503:physiopathology; D015497:HIV-1 / Q000472:pathogenicity* / Q000502:physiology; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1; D016297:Mutagenesis, Site-Directed; D010449:Peptide Mapping; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D012694:Serine / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D014779:Virus Replication
chemical_list: D012694:Serine; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1