Molecular cloning of Ca2+/calmodulin-dependent protein kinase phosphatase

Calmodulin-dependent protein kinase (CaM-kinase) phosphatase dephosphorylat es and concomitantly deactivates CaM-kinase II activated upon autophosphory lation, and CaM-kinases IV and I activated upon phosphorylation by CaM-kina se kinase , suggesting that CaM-kinase phosphatase plays important roles in the function of Ca2+ in the cell, because the three multifunctional CaM-ki nases (CaM-kinases I, II, and IV) are thought to be the key enzymes in the Ca2+-signaling system. In the present study, cDNA for CaM-kinase phosphatas e was cloned from a rat brain cDNA library. The coded protein consisted of 450 amino acids with a molecular weight of 49,165. Western blot analysis sh owed the ubiquitous tissue distribution of CaM-kinase phosphatase. Immunocy tochemical analysis revealed that CaM-kinase phosphatase is evenly distribu ted outside the nucleus in a cell.