title: NADPH oxidase 5 (NOX5) interacts with and is regulated by calmodulin.
abstract: Superoxide generation by NADPH oxidase 5 (NOX5) is regulated by Ca(2+) through intramolecular activation of the C-terminal catalytic domain by the EF-hand-containing N-terminal regulatory domain. The C terminus contains a consensus calmodulin-binding domain (CaMBD), which, however, is not the binding site of the N-terminal regulatory domain. Here we show by pull down, cross-linking, fluorimetry and by enzymatic assays, that calmodulin binds to this CaMBD in a Ca(2+)-dependent manner, changes its conformation and increases the Ca(2+) sensitivity of the N terminus-regulated enzymatic activity. This mechanism represents an additional sophistication in the regulation of superoxide production by NOX5.
authors.affiliation: Department of Biochemistry, University of Geneva, Geneva 4, Switzerland.
authors.forename: Fabiana
authors.initials: F
authors.lastname: Tirone
authors.forename: Jos A
authors.initials: JA
authors.lastname: Cox
mesh_terms: D000818:Animals; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000378:metabolism* / Q000502:physiology; D002417:Cattle; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D013481:Superoxides / Q000378:metabolism
chemical_list: D002147:Calmodulin; D008565:Membrane Proteins; D013481:Superoxides; D000074664:NADPH Oxidase 5; D019255:NADPH Oxidases; C431571:NOX5 protein, human; D002118:Calcium