title: Identification and characterisation of a type-1 protein phosphatase from the okadaic acid-producing marine dinoflagellate Prorocentrum lima.
abstract: The unicellular marine dinoflagellate, Prorocentrum lima, an established producer of okadaic acid (OA), was shown to contain a type-1 protein phosphatase (PP-1) the biochemical profile of which on Mono-Q and Superdex-75 fast protein liquid chromatography was identical to the catalytic subunit of PP-1 from rabbit skeletal muscle. Purified P. lima PP-1 (apparent molecular mass 37.5 kDa) was highly sensitive to inhibition by mammalian protein phosphatase inhibitor-1 and inhibitor-2, and to OA itself. A 6-7-fold increase in OA production by P. lima, when grown under controlled conditions, correlated with an up to 300-fold increase in P. lima PP-1 activity. Furthermore, P. lima did not contain any detectable type-2A protein phosphatase activity. This study represents the first identification of a serine/threonine protein phosphatase in a dinoflagellate.
authors.affiliation: Department of Biochemistry, University of Alberta, Edmonton, Canada.
authors.forename: M P
authors.initials: MP
authors.lastname: Boland
authors.forename: M F
authors.initials: MF
authors.lastname: Taylor
authors.forename: C F
authors.initials: CF
authors.lastname: Holmes
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D003600:Cytosol / Q000201:enzymology; D004141:Dinoflagellida / Q000201:enzymology* / Q000378:metabolism; D004988:Ethers, Cyclic / Q000378:metabolism*; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D004988:Ethers, Cyclic; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases