AEGiS-12IAC: Role of HIV-1 capsid phosphorylation in viral infection.

12th International AIDS Conference

Geneva, Switzerland - June 28-July 3, 1998

Role of HIV-1 capsid phosphorylation in viral infection.

Int Conf AIDS 1998 Jun 28-Jul 3; 12:9 (abstract no. 11135)

Cartier C, Sivard P, Tranchat C, Desgranges C, Boyer V
INSERM, Unite 271, Lyon, France.

BACKGROUND: Our previous study showed that two cellular protein kinases are incorporated into HIV-1 virions. One of those protein kinases is the ERK2 Mitogen-Activated protein kinase. We also detected the phosphorylation of the p24 capsid protein in the viral particles.

OBJECTIVES: To study the role of p24 phosphorylation during viral life cyle.

METHODS: In vitro phosphorylation assays using GST viral fusion proteins and recombinant kinases. Site-directed mutagenesis of each serine residue of p24. Characterisation of those mutant viruses in transfection and infection assays. Study of viral proteins maturation process by Western-blot analysis.

RESULTS: We showed by in vitro binding and phosphorylation experiments that the viral capsid was not phosphorylated by ERK2 MAPK. By site-directed mutagenesis using pNL4-3 infections clone, we generated 9 mutants corresponding to the substitution of each serine residue by alanine. One of those showed a reduced Reverse Transcriptase activity and p24 level compared to wild type virus after transfection of 293 cells. By Western-blot experiments, the maturation process of viral proteins was analysed. Moreover, two additional mutants demonstrated a very weak capacity to induce syncitia formation in the C8166 cell infection assay.

CONCLUSION: Those preliminary results suggest a direct link between p24 phosphorylation and viral infectivity.

Keywords: AEGIS, HIV-1, Capsid, Phosphorylation, Virion, Capsid Proteins, p42 MAP Kinase, HIV Infections, Virus Diseases, Mitogen-Activated Protein Kinases, Blotting, Western, Mutagenesis, Site-Directed, Serine, Viral Proteins, In Vitro, ICA12
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