Effect of Inhibitors of Protein Phosphatase 1 and 2A on Erythroid Colony Formation: An Investigation of the Specificities of Inhibitors

To investigate the possible involvement of protein phosphatase (PP)1 and PP2A in the process of erythropoiesis, we assessed the effect of PP1 and PP2A Inhibitors on erythroid colony formation using an in vitro colony formation assay. Okadaic acid (OKA), calyculin A (Cal-A) and tautomycin suppressed colony formation but 1-nor-okadaone did not. These results soggest that PP1 and PP2A both play an important role in erythropoiesis. Furthermore, higher concentrations of tautomycin were needed to suppress colony formetion compored to concentrations of OKA and Cal-A. The torget enzyme of inhibitors in eruthropoiesis may be PP2A.