Modulation of HIV-1 Rev protein abundance and activity by polyubiquitination with unconventional Lys-33 branching.
The HIV-1 Rev protein plays a key role in virus replication by allowing export to the cytoplasm of unspliced or singly-spliced RNAs. In this report, we investigated whether Rev is modified by ubiquitination or sumoylation. Whereas no evidence of sumoylation was obtained, transient expression experiments showed that ubiquitin conjugates to Rev as high molecular weight polyubiquitin chains. Mutation of the three lysine residues of Rev showed that the site of ubiquitin conjugation is Lys-115. Experiments with ubiquitin mutants including a single lysine at every seven possible position indicated that branching of the polyubiquitin chains mainly involves Lys-33. Mutation of Rev Lys-115 to arginine reduces markedly the steady state amount of the protein, but does not impair its ability to export RNA via the Rev response element. These observations support the notion that polyubiquitination of Rev stabilizes the viral protein but hinders its activity.
Vitte
Anne-Laure
AL
Laboratoire de Biologie Moléculaire de la Cellule, UMR5161 CNRS/ENS de Lyon, IFR 128 Biosciences Lyon Gerland, 46 Allée d'Italie, 69364 Lyon Cedex 07, France.
Buchsbaum
Samuel
S
Jalinot
Pierre
P
D019943:Amino Acid Substitution; D001665:Binding Sites; D015694:Gene Products, rev / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D015497:HIV-1; D008239:Lysine / Q000378:metabolism*; D011108:Polymers; D011499:Protein Processing, Post-Translational; D025842:SUMO-1 Protein / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism*; D054321:rev Gene Products, Human Immunodeficiency Virus
D015694:Gene Products, rev; D011108:Polymers; D025842:SUMO-1 Protein; D025801:Ubiquitin; D054321:rev Gene Products, Human Immunodeficiency Virus; D008239:Lysine