Involvement of the betaTrCP in the ubiquitination and stability of the HIV-1 Vpu protein.

Nadia Belaïdouni, Christelle Marchal, Richard Benarous, Corinne Besnard-Guérin

Institut Cochin, Université Paris Descartes, CNRS (UMR 8104), Paris, France.

Biochemical and biophysical research communications 2007 Jun 8

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The human immunodeficiency virus type 1 (HIV-1) Vpu protein binds to the CD4 receptor and targets it to the proteasome for degradation. This process requires the recruitment of human betaTrCP, a component of the Skp1-Cullin-F box (SCF) ubiquitin ligase complex, that interacts with phosphorylated Vpu molecules. Vpu, unlike other ligands of betaTrCP, has never been reported to be degraded. We provide evidence that Vpu, itself, is ubiquitinated and targeted for degradation by the proteasome. We demonstrate that the mutant Vpu2.6, which cannot interact with betaTrCP, is stable and, unlike wild-type Vpu, is not polyubiquitinated. These results suggest that betaTrCP is involved in Vpu polyubiquitination.

Citation

Nadia Belaïdouni, Christelle Marchal, Richard Benarous, Corinne Besnard-Guérin. Involvement of the betaTrCP in the ubiquitination and stability of the HIV-1 Vpu protein. Biochemical and biophysical research communications. 2007 Jun 8;357(3):688-93