Mitochondrial ATP synthases cluster as discrete domains that reorganize with the cellular demand for oxidative phosphorylation.
Résumé
: Mitochondria are double membrane-bounded organelles that form a dynamic tubular network. Mitochondria energetic functions depend on a complex internal architecture. Cristae, inner membrane invaginations that folds into the matrix space, are proposed to be the site of oxidative phosphorylation (OXPHOS), reactions by which ATP synthase produces ATP. ATP synthase is also thought to have a role in cristae morphogenesis. To date, the exploration of the processes regulating mitochondrial internal compartmentalization have been mostly limited to electron microscopy. Here, we describe ATP synthase localization in living yeast cells and show that it clusters as discrete inner membrane domains. These domains are dynamic within the mitochondrial network. They are impaired in mutants defective in cristae morphology and partially overlap with the cristae-associated MICOS/MINOS/MITOS complex. Finally, ATP synthase occupancy increases with the cellular demand for OXPHOS. Overall our data suggest that domains in which ATP synthases are clustered correspond to mitochondrial cristae. Being able to follow mitochondria sub-compartments in living yeast cells opens new avenues to explore the mechanisms involved in inner membrane remodelling, an architectural feature crucial for mitochondrial activities.