title: NOX4 in Mitochondria: Yeast Two-Hybrid-Based Interaction with Complex I Without Relevance for Basal Reactive Oxygen Species?
abstract: NADPH oxidases (NOXs) represent the only known dedicated source of reactive oxygen species (ROS) and thus a prime therapeutic target. Type 4 NOX is unique as it produces H2O2, is constitutively active, and has been suggested to localize to cardiac mitochondria, thus possibly linking mitochondrial and NOX-derived ROS formation. The aim of this study was to identify NOX4-binding proteins and examine the possible physiological localization of NOX4 to mitochondria and its impact on mitochondrial ROS formation. We here provide evidence that NOX4 can, in principle, enter protein-protein interactions with mitochondrial complex I NADH dehydrogenase subunits, 1 and 4L. However, under physiological conditions, NOX4 protein was neither detectable in the kidney nor in cardiomyocyte mitochondria. The NOX inhibitor, GKT136901, slightly reduced ROS formation in cardiomyocyte mitochondria, but this effect was observed in both wild-type and Nox4(-/-) mice. NOX4 may thus associate with mitochondrial complex I proteins, but in cardiac and renal mitochondria under basal conditions, expression is beyond our detection limits and does not contribute to ROS formation.
authors.affiliation: 1 Physiologisches Institut, Justus-Liebig Universität , Gießen, Germany .
authors.forename: Christine
authors.initials: C
authors.lastname: Hirschhäuser
authors.affiliation: 1 Physiologisches Institut, Justus-Liebig Universität , Gießen, Germany .
authors.forename: Julia
authors.initials: J
authors.lastname: Bornbaum
authors.affiliation: 1 Physiologisches Institut, Justus-Liebig Universität , Gießen, Germany .
authors.forename: Anna
authors.initials: A
authors.lastname: Reis
authors.affiliation: 1 Physiologisches Institut, Justus-Liebig Universität , Gießen, Germany .
authors.forename: Sabrina
authors.initials: S
authors.lastname: Böhme
authors.affiliation: 2 Neuroscience Institute , CNR, Padova, Italy .
authors.forename: Nina
authors.initials: N
authors.lastname: Kaludercic
authors.affiliation: 2 Neuroscience Institute , CNR, Padova, Italy .
authors.forename: Roberta
authors.initials: R
authors.lastname: Menabò
authors.affiliation: 3 Dipartimento di Scienze Biomediche, Università degli Studi di Padova , Padova, Italy .
authors.forename: Fabio
authors.initials: F
authors.lastname: Di Lisa
authors.affiliation: 1 Physiologisches Institut, Justus-Liebig Universität , Gießen, Germany .
authors.forename: Kerstin
authors.initials: K
authors.lastname: Boengler
authors.affiliation: 4 King's College London , BHF Centre of Excellence, The James Black Centre, London, United Kingdom .
authors.forename: Ajay M
authors.initials: AM
authors.lastname: Shah
authors.affiliation: 1 Physiologisches Institut, Justus-Liebig Universität , Gießen, Germany .
authors.forename: Rainer
authors.initials: R
authors.lastname: Schulz
authors.affiliation: 5 Department of Pharmacology, CARIM, and Maastricht Institute for Advanced Studies, Maastricht University , Maastricht, The Netherlands .
authors.forename: Harald H H W
authors.initials: HH
authors.lastname: Schmidt
mesh_terms: D000818:Animals; D042967:Electron Transport Complex I / Q000378:metabolism; D057230:Limit of Detection; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008929:Mitochondria, Heart / Q000201:enzymology; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000378:metabolism*; D011485:Protein Binding; D017382:Reactive Oxygen Species / Q000378:metabolism; D020798:Two-Hybrid System Techniques
chemical_list: D017382:Reactive Oxygen Species; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C422943:Nox4 protein, mouse; D042967:Electron Transport Complex I