Calcineurin is a calmodulin-dependent protein phosphatase
Yang, S.D.; Tallant, E.A.; Cheung, W.Y.
Biochemical and Biophysical Research Communications 106(4): 1419-1425
1982
ISSN/ISBN: 0006-291X PMID: 6288046 Document Number: 191372
Calcineurin, one of the major calmodulin-binding proteins in the brain, dephosphorylates a phosphorylated protein termed inhibitor-1, a potent inhibitor of protein phosphatase 1. The phosphatase activity was Ca2+- and calmodulin-dependent and was reversed by EGTA [ethylene glycol bis(.beta.-aminoethyl ether)-N,N,N',N'-tetraacetic acid] or trifluoperazine, an antagonist of calmodulin. Using a radioimmunoassay of calcineurin and a phosphatase activity assay, the 2 activities coincided in a sucrose density gradient and in a non-denaturing polyacrylamide gel. Calcineurin is a calmodulin-dependent protein phosphatase.