Figure 1From: CD4+CD25+ T regulatory cells from FIV+ cats induce a unique anergic profile in CD8+lymphocyte targetsA schematic representation of the relative protein levels during the normal progression from G 1 to S phase of the cell cycle. In T lymphocytes during the normal progression of the cell cycle, D cyclins (D2 and D3, D2 not shown) are expressed sequentially starting in late G0/early G1. At approximately the same time the relative level of the CDKI p21cip1 begins to increase and then plateaus during late G1/early S phase. p21cip1 inhibits cyclin E until the cellular machinery is ready for a synchronized G1 to S phase transition. Cyclin E levels begin to rise during late G1and peak during early S phase. Separation of Rb from E2F proteins and hyperphosphorylation of Rb at multiple sites signals the irreversible commitment (IC, double line) to S phase and cell cycle progression. (Note: only the proteins examined in Figures 2-5 are represented here.)Back to article page