Isolation of a cDNA likely to encode a novel Ca2+-dependent/calmodulin-stimulated protein phosphatase

Complementary DNA encoding a novel protein phosphatase catalytic subunit has been isolated from a rabbit brain library. The deduced protein sequence is more similar to the major Ca2+-dependent/calmodulin-stimulated protein phosphatase (2B) in brain (55% identity) than to protein phosphatases 1 and 2A (38-39% identity). A putative calmodulin-binding domain is present C-terminal to the catalytic domain, which closely resembles that of the mouse brain enzyme. These findings represent the first indication that at least two distinct Ca2+-dependent/calmodulin-stimulated protein phosphatases are present in mammalian brain.