FIG. 6.

Summary of impacts of a CCR5 strain of HIV-1 on cell cycle regulators in MDM. Progression through G₂ is regulated by phosphorylation states of the CDC2-cyclin B2 complex. Reversible phosphorylation reactions of the CDC2-cyclin B2 complex determine active (phosphorylated) or subsequent inactive (hyperphosphorylated) states. Hyperphosphorylated CDC2-cyclin B2 complex can be reactivated through dephosphorylation catalyzed by CDC25. HIV-1 exposure induces the expression of cell cycle regulators (PP2A, BRCA1/GADD45, p21^Cip1, and YWHAE) involved in arresting MDM in G₂. Inactive CDC2-cyclin B2 complex is promoted in HIV-1-treated cells (boldface arrows). Red indicates factors that were induced, and green indicates factors that were suppressed. Ovals, diamonds, and hexagons indicate whether the differential expression was detected at the level of mRNA, protein, or both, respectively.