Figure 3

SiRNA depletion of PPM1A increases CDK9 T-loop phosphorylation in resting CD4⁺T cells. Resting CD4⁺T cells from three healthy blood donors were nucleofected with siRNA against PPM1A or control siRNA on two consecutive days. Cell extracts were prepared 48 hours post-Nucleofection and evaluated for PPM1A, T-loop phosphorylated CDK9 (pCDK9), total CDK9, α-Tubulin and β-Actin (loading control) in immunoblots. Protein levels shown on top of panels were quantified by normalizing to α-Tubulin or β-Actin and set at 1.0 in control siRNA-transfected cells.