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


RESULTS
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 theta during Vprv-induced G2,M arrest. By contrast, a cell-cycle-arrest-dead Vpr mutant failed to augment 14-3-3 theta association with Cdk1 and CyclinB1. Moreover, G2,M arrest caused by HIV-1 infection strongly correlated with a disruption in 14-3-3 theta 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 beta.


CONCLUSIONS
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.
Bolton
Diane L
DL
Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health Bethesda, MD 20892, USA. dbolton@nih.gov
Barnitz
Robert A
RA
Sakai
Keiko
K
Lenardo
Michael J
MJ
D048948:14-3-3 Proteins / Q000378:metabolism / Q000502:physiology*; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000378:metabolism* / Q000821:virology; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000378:metabolism* / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D002999:Clone Cells; D055785:Gene Knockdown Techniques; D016336:Gene Products, vpr / Q000378:metabolism / Q000502:physiology*; D015497:HIV-1 / Q000502:physiology*; D006801:Humans; D019169:Jurkat Cells; D011485:Protein Binding / Q000502:physiology; D014779:Virus Replication / Q000502:physiology
D048948:14-3-3 Proteins; D018797:Cell Cycle Proteins; D016336:Gene Products, vpr