title: Identification of a 42 kDa protein as a substrate of protein phosphatase 1 in cilia from Paramecium.
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.
authors.affiliation: Pharmazeutisches Institut der Universität, Tübingen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Klumpp
authors.forename: J E
authors.initials: JE
authors.lastname: Schultz
mesh_terms: D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D015220:Calcium Channels / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D002923:Cilia / Q000737:chemistry* / Q000201:enzymology; D000242:Cyclic AMP / Q000378:metabolism; D004988:Ethers, Cyclic / Q000494:pharmacology; D008387:Marine Toxins; D052998:Microcystins; D019319:Okadaic Acid; D010247:Paramecium / Q000032:analysis* / Q000187:drug effects; D010456:Peptides, Cyclic / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000187:drug effects / Q000378:metabolism*; D010750:Phosphoproteins / Q000302:isolation & purification* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D054645:Protein Phosphatase 1; D015800:Protozoan Proteins / Q000302:isolation & purification* / Q000378:metabolism; D011714:Pyrans; D013141:Spiro Compounds
chemical_list: D000935:Antifungal Agents; D015220:Calcium Channels; D004988:Ethers, Cyclic; D008387:Marine Toxins; D052998:Microcystins; D010456:Peptides, Cyclic; D010750:Phosphoproteins; D015800:Protozoan Proteins; D011714:Pyrans; D013141:Spiro Compounds; C053079:tautomycin; D019319:Okadaic Acid; D000242:Cyclic AMP; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D000252:Calcium-Transporting ATPases; C057862:cyanoginosin LR