1. Identification of a 42 kDa protein as a substrate of protein phosphatase 1 in cilia from Paramecium.
- Author
-
Klumpp S and Schultz JE
- Subjects
- Animals, Antifungal Agents pharmacology, Calcium Channels metabolism, Calcium-Transporting ATPases metabolism, Cilia enzymology, Cyclic AMP metabolism, Ethers, Cyclic pharmacology, Marine Toxins, Microcystins, Okadaic Acid, Paramecium drug effects, Peptides, Cyclic pharmacology, Phosphoprotein Phosphatases drug effects, Phosphoproteins metabolism, Phosphorylation drug effects, Protein Phosphatase 1, Protozoan Proteins metabolism, Cilia chemistry, Paramecium analysis, Phosphoprotein Phosphatases metabolism, Phosphoproteins isolation & purification, Protozoan Proteins isolation & purification, Pyrans, Spiro Compounds
- Abstract
Okadaic acid, a specific inhibitor of protein phosphatase 1 in Paramecium causes sustained backward swimming in response to depolarising stimuli (S. Klumpp et al. (1990) EMBO J. 9, 685). Here, we employ okadaic acid, tautomycin, microcystin LR and inhibitor 1 as phosphatase inhibitors to identify a 42 kDa protein in the excitable ciliary membrane that is dephosphorylated by protein phosphatase 1. Identification of the 42 kDa protein was facilitated by the finding that the protein kinase responsible for its phosphorylation uses Ca-ATP as a substrate just as effectively as Mg-ATP. Notably, dephosphorylation of the 42 kDa protein is specifically inhibited by cyclic AMP; cyclic GMP has no effect.
- Published
- 1991
- Full Text
- View/download PDF