PPP1R2 is an inhibitor of protein-phosphatase 1 and forms heterodimer with PP1. Phosphorylation on Thr-73 by GSK3 activates PP1 by dissociating the PP1-PPP1R2 complex. Phosphorylation on Ser-44 by ATM activates PP1 by dissociating the PP1-PPP1R2 complex. Recombinant human PPP1R2 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.