PPM1A is expressed at high levels in resting CD4+T cells. Resting CD4+T-cells isolated by negative selection from two healthy donors were activated with anti-CD3/CD28 Dynabeads. Cell lysates were prepared from resting CD4+T cells and cells activated for 48 hours. Immunoblots were performed to measure levels of: A. total CDK9, T-loop phosphorylated CDK9 (pCDK9), PPM1A and β-Actin (loading control) and B. total CDK9 and CDK7, T-loop phosphorylated CDK9 (pCDK9) and CDK7 (pCDK7), and HSP-70 (loading control). Protein levels shown on top of panels were quantified by normalizing to β-Actin or Hsp70 and set at 1.0 in resting CD4+T cells.