title: Specificity of different isoforms of protein phosphatase-2A and protein phosphatase-2C studied using site-directed mutagenesis of HMG-CoA reductase.
abstract: We have expressed the catalytic domain of Chinese hamster HMG-CoA reductase, and 13 point mutations involving the region around the single phosphorylation site for AMP-activated protein kinase. After phosphorylation, these were used to test the specificity of isoforms of protein phosphatase-2A [bovine PP2A(C) (catalytic subunit) and PP2A1 (ABC heterotrimer)] and protein phosphatase-2C (human alpha; mouse alpha, beta1, beta2, beta3, beta4, beta5). PP2A1 had > 50-fold higher activity for HMG-CoA reductase variants than PP2A(C), but their relative selectivity for different variants was similar. Although the specificities of PP2A and PP2C were distinct, no dramatic differences in selectivity were observed between different PP2C isoforms.
authors.affiliation: Biochemistry Department, The University, Dundee, Scotland, UK.
authors.forename: Y P
authors.initials: YP
authors.lastname: Ching
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Tamura
authors.forename: D G
authors.initials: DG
authors.lastname: Hardie
mesh_terms: D055372:AMP-Activated Protein Kinases; D000818:Animals; D016466:CHO Cells; D002417:Cattle; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D006801:Humans; D006903:Hydroxymethylglutaryl CoA Reductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007527:Isoenzymes / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D009097:Multienzyme Complexes / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010749:Phosphoprotein Phosphatases / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D017354:Point Mutation; D011494:Protein Kinases / Q000378:metabolism; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C; D017346:Protein Serine-Threonine Kinases; D011994:Recombinant Proteins / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D013379:Substrate Specificity
chemical_list: D007527:Isoenzymes; D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; D006903:Hydroxymethylglutaryl CoA Reductases; D011494:Protein Kinases; C526182:PRKAB1 protein, human; C526183:PRKAB2 protein, human; D017346:Protein Serine-Threonine Kinases; D055372:AMP-Activated Protein Kinases; C000607456:PPM1A protein, human; C000607457:PPM1B protein, human; C000607460:PPM1G protein, human; C087358:PTC1 protein, S cerevisiae; D010749:Phosphoprotein Phosphatases; D054648:Protein Phosphatase 2; D000071636:Protein Phosphatase 2C