Systematic mapping of contact sites reveals tethers and a function for the peroxisome-mitochondria contact

Abstract

The understanding that organelles are not floating in the cytosol, but rather held in an organized yet dynamic interplay through membrane contact sites, is altering the way we grasp cell biological phenomena. However, we still have not identified the entire repertoire of contact sites, their tethering molecules and functions. To systematically characterize contact sites and their tethering molecules here we employ a proximity detection method based on split fluorophores and discover four potential new yeast contact sites. We then focus on a little-studied yet highly disease-relevant contact, the Peroxisome-Mitochondria (PerMit) proximity, and uncover and characterize two tether proteins: Fzo1 and Pex34. We genetically expand the PerMit contact site and demonstrate a physiological function in β-oxidation of fatty acids. Our work showcases how systematic analysis of contact site machinery and functions can deepen our understanding of these structures in health and disease.

Abstract

The internal organization of the cell has been enriched by the discovery that organelles establish membrane contact sites, however the entire repertoire of these contacts is still being explored. Here the authors systematically identify the landscape of cellular contact sites in yeast, discovering four potential novel contact sites and two tether proteins for the peroxisome-mitochondria contact site.