Hsp40 Facilitates Nuclear Import of the Human Immunodeficiency Virus Type 2 Vpx-Mediated Preintegration Complex

Authors

Xiaogang Cheng, Washington University School of Medicine
Michael Belshan, Creighton UniversityFollow
Lee Ratner, Washington University School of Medicine

Date of this Version

February 2008

Comments

Published in JOURNAL OF VIROLOGY, Feb. 2008, p. 1229–1237 Vol. 82, No. 3. 0022-538X doi:10.1128/JVI.00540-07 Copyright © 2008, American Society for Microbiology. Used by permission.

Abstract

Human immunodeficiency virus type 2 (HIV-2) Vpx is required for nuclear translocation of the viral preintegration complex (PIC) in quiescent cells. In order to decipher the mechanism of action of Vpx, a cDNA library was screened with the yeast two-hybrid assay, resulting in the identification of heat shock protein 40, Hsp40/DnaJB6, as a Vpx-interactive protein. Interaction with Vpx was confirmed by glutathione S-transferase (GST) pull-down and coimmunoprecipitation assays. Overexpression of Hsp40/DnaJB6 enhanced Vpx nuclear import, whereas overexpression of a nuclear localization mutant of Hsp40/DnaJB6 (H31Q) or down-regulation of Hsp40/DnaJB6 by small interfering RNA (siRNA) reduced the nuclear import of Vpx. Hsp40/DnaJB6 competed with the Pr55^Gag precursor protein for the binding of Vpx and incorporation into virus-like particles. Overexpression of Hsp40/DnaJB6 promoted viral PIC nuclear import, whereas siRNA down-regulation of Hsp40/DnaJB6 inhibited PIC nuclear import. These results demonstrate a role for Hsp40/DnaJB6 in the regulation of HIV-2 PIC nuclear transport.