Protein phosphatase inhibitor calyculin A induces hyperphosphorylation of cytokeratins and inhibits amylase exocytosis in the rat parotid acini.


Calyculin A, a protein phosphatase inhibitor with a chemical structure completely different from that of okadaic acid, reproduced the inhibitory effect of okadaic acid on cyclic AMP-mediated amylase release from rat parotid acinar cells. Calyculin A markedly enhanced phosphorylation of cytokeratins in the cytoskeletal fraction of the cells, whereas cAMP had… (More)