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 suggest that PP1 and PP2A both play an important role in erythropoiesis. Furthermore, higher concentrations of tautomycin were needed to suppress colony formation compared to concentrations of OKA and Cal-A. The target enzyme of inhibitors in erythropoiesis may be PP2A.
KawadaETamuraJKubotaKMurakamiHNaruseTTsuchiyaJ: Possible involvement of protein kinase C in the aberrant regulation of erythropoiesis in polycythemia vera. Leuk Res1997; 21: 101–105
2.
MoritaKNishikawaMKobayashiKDeguchiKItoMNakanoT: Augmentation of retinoic acid-induced granulocytic differentiation in HL-60 leukemia cells by serine/threonine protein phosphatase inhibitors. FEBS Lett1992; 314: 340–344
3.
OmaySBOgasawaraHToyodaHNakaiKShimaHNagaoM: Translocation of protein phosphatase 1 catalytic subunits during 1,25-dehydroxyvitamin D3-induced monocytic differentiation of HL-60 cells. Cancer Res1995; 55: 774–780
4.
KatayamaNNishikawaMShimizuNKomadaFSekineTMinamiB: A role for protein kinase C in growth of human erythroid progenitor cells. Leuk Res1992; 16: 145–151
5.
KatayamaNNishikawaMKomodaFMinamiMShirakawaS: A role for calmodulin in the growth of human hematopoietic progenitor cells. Blood1990; 75: 1446–1454
6.
IshiharaHMartinBLBrautigenDLKarakiHOzakiHKatoY: Calyculin A and Okadaic acid: inhibitors of protein phosphatase activity. Biochem Biophys Res Commun1989; 50: 621–626
7.
MacintoshCKlumppS: Tautomycin from the bactirium streptomyces verticillatus. Another potent and specific inhibitor for protein phosphatases 1 and 2A. FEBS Lett1990; 277: 137–140
8.
LiuJFarmerJDJrLaneWSFriedmanJWeissmanISchreiberSL: Calcineurin is a common target of cyclophilin-cyclosporin A and FKBP-FK506 complexes. Cell1991; 66: 807–815
9.
O'KeefeSJTamuraJKincaidRLTocciMJO'NeillEA: FK-506- and CsA-sensitive activation of the interleukin-2 promoter by calcineurin. Nature1992; 357: 692–697
10.
PeachellPTMundayMR: Regulation of human mast cell function by phosphatase inhibitors. J Immunol1993; 151: 3808–3816
11.
YangYCCiarlettaABTemplePAChungMPKovacicSWitek-GianottiJS: Human IL-3 (multi-CSF) identification by expression cloning of a novel hematopoietic growth factor related to murine IL-3. Cell1986; 47: 3–10
12.
OgawaMMatsuzakiYNishikawaSHayashiSKunisadaT: Expression and function of c-kit in hemopoietic progenitor cells. J Exp Med1991; 174: 63–71
