title: Membranous adenylyl cyclase 1 activation is regulated by oxidation of N- and C-terminal methionine residues in calmodulin.
abstract: Membranous adenylyl cyclase 1 (AC1) is associated with memory and learning. AC1 is activated by the eukaryotic Ca(2+)-sensor calmodulin (CaM), which contains nine methionine residues (Met) important for CaM-target interactions. During ageing, Met residues are oxidized to (S)- and (R)-methionine sulfoxide (MetSO) by reactive oxygen species arising from an age-related oxidative stress. We examined how oxidation by H2O2 of Met in CaM regulates CaM activation of AC1. We employed a series of thirteen mutant CaM proteins never assessed before in a single study, where leucine is substituted for Met, in order to analyze the effects of oxidation of specific Met. CaM activation of AC1 is regulated by oxidation of all of the C-terminal Met in CaM, and by two N-terminal Met, M36 and M51. CaM with all Met oxidized is unable to activate AC1. Activity is fully restored by the combined catalytic activities of methionine sulfoxide reductases A and B (MsrA and B), which catalyze reduction of the (S)- and (R)-MetSO stereoisomers. A small change in secondary structure is observed in wild-type CaM upon oxidation of all nine Met, but no significant secondary structure changes occur in the mutant proteins when Met residues are oxidized by H2O2, suggesting that localized polarity, flexibility and structural changes promote the functional changes accompanying oxidation. The results signify that AC1 catalytic activity can be delicately adjusted by mediating CaM activation of AC1 by reversible Met oxidation in CaM. The results are important for memory, learning and possible therapeutic routes for regulating AC1.
authors.affiliation: Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str.1, D-30625 Hannover, Germany.
authors.forename: Carolin
authors.initials: C
authors.lastname: Lübker
authors.affiliation: Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602-2556, USA.
authors.forename: Ramona J Bieber
authors.initials: RJ
authors.lastname: Urbauer
authors.affiliation: Department of Pharmacology and Toxicology, University of Kansas, 1251 Wescoe Hall Drive, Lawrence, KS 66045, USA.
authors.forename: Jackob
authors.initials: J
authors.lastname: Moskovitz
authors.affiliation: Institute of Pharmacy, University of Regensburg, Universitätsstr. 31, D-93053 Regensburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Dove
authors.affiliation: Institute of Toxicology, Hannover Medical School, Carl-Neuberg-Str.1, D-30625 Hannover, Germany.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Weisemann
authors.affiliation: Institute of Bioanalytical Chemistry, University of Leipzig, Deutscher Platz 5, D-04103 Leipzig, Germany.
authors.forename: Maria
authors.initials: M
authors.lastname: Fedorova
authors.affiliation: Department of Chemistry, University of Georgia, 140 Cedar Street, Athens, GA 30602-2556, USA.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Urbauer
authors.affiliation: Institute of Pharmacology, Hannover Medical School, Carl-Neuberg-Str.1, D-30625 Hannover, Germany. Electronic address: seifert.roland@mh-hannover.de.
authors.forename: Roland
authors.initials: R
authors.lastname: Seifert
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002147:Calmodulin / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007313:Insecta; D008715:Methionine / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D061987:Sf9 Cells
chemical_list: D002147:Calmodulin; D008715:Methionine; D006861:Hydrogen Peroxide; D000262:Adenylyl Cyclases; C106670:adenylyl cyclase 1
keywords: Adenylyl cyclase; Ageing; Calmodulin; Methionine oxidation; Reactive oxygen species