Glutathione-dependent depalmitoylation of phospholemman by peroxiredoxin 6
Jacqueline Howie,
Lindsay B. Tulloch,
Elaine Brown,
Louise Reilly,
Fiona B. Ashford,
Jennifer Kennedy,
Krzysztof J. Wypijewski,
Karen L. Aughton,
Jason K.C. Mak,
Michael J. Shattock,
Niall J. Fraser,
William Fuller
Affiliations
Jacqueline Howie
School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK; Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
Lindsay B. Tulloch
Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
Elaine Brown
School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK
Louise Reilly
Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
Fiona B. Ashford
Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
Jennifer Kennedy
School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK; Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
Krzysztof J. Wypijewski
School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK; Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK
Karen L. Aughton
School of Cardiovascular and Metabolic Medicine and Sciences, King’s College London, London, UK
Jason K.C. Mak
School of Cardiovascular and Metabolic Medicine and Sciences, King’s College London, London, UK
Michael J. Shattock
School of Cardiovascular and Metabolic Medicine and Sciences, King’s College London, London, UK
Niall J. Fraser
Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, UK; Corresponding author
William Fuller
School of Cardiovascular and Metabolic Health, University of Glasgow, Glasgow, UK; Corresponding author
Summary: Phospholemman (PLM) regulates the cardiac sodium pump: PLM phosphorylation activates the pump whereas PLM palmitoylation inhibits its activity. Here, we show that the anti-oxidant protein peroxiredoxin 6 (Prdx6) interacts with and depalmitoylates PLM in a glutathione-dependent manner. Glutathione loading cells acutely reduce PLM palmitoylation; glutathione depletion significantly increases PLM palmitoylation. Prdx6 silencing abolishes these effects, suggesting that PLM can be depalmitoylated by reduced Prdx6. In vitro, only recombinant Prdx6, among several peroxiredoxin isoforms tested, removes palmitic acid from recombinant palmitoylated PLM. The broad-spectrum depalmitoylase inhibitor palmostatin B prevents Prdx6-dependent PLM depalmitoylation in cells and in vitro. Our data suggest that Prdx6 is a thioesterase that can depalmitoylate proteins by nucleophilic attack via its reactive thiol, linking PLM palmitoylation and hence sodium pump activity to cellular glutathione status. We show that protein depalmitoylation can occur via a catalytic cysteine in which substrate specificity is determined by a protein-protein interaction.
