Phosphorylation of HIV Nef by cAMP-dependent protein kinase.
Nef, a multifunctional accessory protein of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV), is important for disease progression. Nef downmodulates CD4 and MHC class I expression, alters host-cell signal transduction pathways, and enhances viral replication. We have identified a novel interaction between Nef and cAMP-dependent kinase (PKA). N-terminal serine residues Ser6,9 of HIVNL4-3 Nef and Ser10 of SIVmac239 Nef were phosphorylated by PKA in a cell-free system; intracellularly, only Ser9 of HIVNL4-3 Nef was phosphorylated by PKA. Mutation of Ser9 to alanine in the context of full-length HIVNL4-3 lowered HIV replication in resting peripheral blood mononuclear cells (PBMC) compared to parental virus. As this mutation played a major role in abrogating the Nef effect on HIV replication in unstimulated primary cells, we postulate that Nef phosphorylation by PKA is an important step in the viral life cycle in resting cells.
Li
Pei Lin
PL
Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Wang
Tao
T
Buckley
Kathleen A
KA
Chenine
Agnès-Laurence
AL
Popov
Sergei
S
Ruprecht
Ruth M
RM
D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D015693:Gene Products, nef / Q000378:metabolism*; D006678:HIV / Q000378:metabolism*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D010766:Phosphorylation; D015302:Simian Immunodeficiency Virus / Q000502:physiology; D014779:Virus Replication; D054311:nef Gene Products, Human Immunodeficiency Virus
D015693:Gene Products, nef; D054311:nef Gene Products, Human Immunodeficiency Virus; D017868:Cyclic AMP-Dependent Protein Kinases