The intra-mitochondrial O-GlcNAcylation system rapidly modulates OXPHOS function and ROS release in the heart
Justine Dontaine, Asma Bouali, Frédéric Daussin, Laurent Bultot, Didier Vertommen, Manon Martin, Raahulan Rathagirishnan, Alexanne Cuillerier, Sandrine Horman, Christophe Beauloye, Laurent Gatto, Benjamin Lauzier, Luc Bertrand, Yan Burelle
Abstract
Protein O-GlcNAcylation is increasingly recognized as an important cellular regulatory mechanism, in multiple organs including the heart. However, the mechanisms leading to O-GlcNAcylation in mitochondria and the consequences on their function remain poorly understood. In this study, we use an in vitro reconstitution assay to characterize the intra-mitochondrial O-GlcNAc system without potential cytoplasmic confounding effects. We compare the O-GlcNAcylome of isolated cardiac mitochondria with that of mitochondria acutely exposed to NButGT, a specific inhibitor of glycoside hydrolase. Amongst the 409 O-GlcNAcylated mitochondrial proteins identified, 191 display increased O-GlcNAcylation in response to NButGT. This is associated with enhanced Complex I (CI) activity, increased maximal respiration in presence of pyruvate-malate, and a striking reduction of mitochondrial ROS release, which could be related to O-GlcNAcylation of specific subunits of ETC complexes (CI, CIII) and TCA cycle enzymes. In conclusion, our work underlines the existence of a dynamic mitochondrial O-GlcNAcylation system capable of rapidly modifying mitochondrial function.