14-3-3 theta binding to cell cycle regulatory factors is enhanced by HIV-1 Vpr

• Main Authors: Sakai Keiko, Barnitz Robert A, Bolton Diane L, Lenardo Michael J
• Format: Article
• Language: English
• Published: BMC 2008-04-01
• Series: Biology Direct
• Online Access: http://www.biology-direct.com/content/3/1/17

<p>Abstract</p> <p>Background</p> <p>Despite continuing advances in our understanding of AIDS pathogenesis, the mechanism of CD4+ T cell depletion in HIV-1-infected individuals remains unclear. The HIV-1 Vpr accessory protein causes cell death, likely through a mechanism related to its ability to arrest cells in the G₂,M phase. Recent evidence implicated the scaffold protein, 14-3-3, in Vpr cell cycle blockade.</p> <p>Results</p> <p>We found that in human T cells, 14-3-3 plays an active role in mediating Vpr-induced cell cycle arrest and reveal a dramatic increase in the amount of Cdk1, Cdc25C, and CyclinB1 bound to 14-3-3 θ during Vpr_v-induced G₂,M arrest. By contrast, a cell-cycle-arrest-dead Vpr mutant failed to augment 14-3-3 θ association with Cdk1 and CyclinB1. Moreover, G₂,M arrest caused by HIV-1 infection strongly correlated with a disruption in 14-3-3 θ binding to centrosomal proteins, Plk1 and centrin. Finally, Vpr caused elevated levels of CyclinB1, Plk1, and Cdk1 in a complex with the nuclear transport and spindle assembly protein, importin β.</p> <p>Conclusion</p> <p>Thus, our data reveal a new facet of Vpr-induced cell cycle arrest involving previously unrecognized abnormal rearrangements of multiprotein assemblies containing key cell cycle regulatory proteins.</p> <p>Reviewers</p> <p>This article was reviewed by David Kaplan, Nathaniel R. Landau and Yan Zhou.</p>