HIV-1 VPR modulates cell cycle G2/M transition through an alternative cellular mechanism other than the classic mitotic checkpoints.

1. Abstract 2. Introduction 3. Cell cycle G2/M control 3.1. The DNA damage and replication checkpoints act through inhibitory phosphorylation of Cdc2 3.2. Vpr-induced G2 arrest acts through inhibitory phosphorylation of Cdc2 but does not use the mitotic checkpoints 4. Possible regulatory steps between Vpr and the cell cycle regulators Wee1 and Cdc25 4.1. Protein phosphatase 2A (PP2A) 4.2. Other cellular proteins which may be involved in Vpr-induced G2 arrest 4.3. Alteration of cellular localization may be important for Vpr-induced G2 arrest 4.4. Structural requirements for G2 arrest and relationship to other Vpr activities 5. Summary and future prospects 6. Acknowledgements 7. References