Cyanobacterial microcystin‐LR is a potent and specific inhibitor of protein phosphatases 1 and 2A from both mammals and higher plants

FEBS Letters

Codd, Geoffrey A.²  MacKintosh, Carol³  Klumpp, Susanne¹  Cohen, Philip³  Beattie, Kenneth A.² 

[1] Pharmazeutisches Institut der Universität Tubingen, Tubingen, FRG;Department of Biological Sciences, University of Dundee, Dundee, Scotland;Protein Phosphorylation Group, Department of Biochemistry, University of Dundee, Dundee, Scotland

关键词: Microcystin;    Cyanobacteria;    Toxin;    Protein phosphatase;    Protein kinase;    Okadaic acid;   

DOI  :  10.1016/0014-5793(90)80245-E

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The cyclic heptapeptide, microcystin-LR, inhibits protein phosphatases 1 (PP1) and 2A (PP2A) with K _i, values below 0.1 nM. Protein phosphatase 2B is inhibited 1000-fold less potently, while six other phosphatases and eight protein kinases tested are unaffected. These results are strikingly similar to those obtained with the tumour promoter okadaic acid. We establish that okadaic acid prevents the binding of microcystin-LR to PP2A, and that protein inhibitors 1 and 2 prevent the binding of microcystin-LR to PP1. We discuss the possibility that inhibition of PP1 and PP2A accounts for the extreme toxicity of microcystin-LR, and indicate its potential value in the detection and analysis of protein kinases and phosphatases.

【 授权许可】

Unknown