Mechanism of action of TAT2 in T cells. a, Effect of inhibiting cell signaling proteins AKT, ERK1/2, and MEK on telomerase activity in cells treated with TAT2 or DMSO (n = 3). T cells from HIV-infected individuals (n = 3) were stimulated with CD2/CD3/CD28 Ab-coated beads for 7 days, followed by a 2-h exposure to one of the pathway inhibitors, then a 24-h treatment with either TAT2 or DMSO, as described in detail in the Materials and Methods section. Telomerase activity was then determined by TRAP. b, Amount of phospho-ERK (p-ERK) in T cells treated with TAT2 or DMSO, as detected by ELISA. Twelve days after stimulation of T cells from HIV-infected donors (n = 3) with CD3/CD28 Ab-coated beads, TAT2 (1 μM) or DMSO (0.1%) was added and cells were harvested at various times after this treatment (15, 30, 60, and 120 min.); the amount of p-ERK1/2 was determined using the ERK1/2 Phospho-Specific Elisa kit a-c, error bars indicate SD. * indicates p value <0.05.