title: AtMic60 Is Involved in Plant Mitochondria Lipid Trafficking and Is Part of a Large Complex.
abstract: The mitochondrion is an organelle originating from an endosymbiotic event and playing a role in several fundamental processes such as energy production, metabolite syntheses, and programmed cell death. This organelle is delineated by two membranes whose synthesis requires an extensive exchange of phospholipids with other cellular organelles such as endoplasmic reticulum (ER) and vacuolar membranes in yeast. These transfers of phospholipids are thought to occur by a non-vesicular pathway at contact sites between two closely apposed membranes. In plants, little is known about the biogenesis of mitochondrial membranes. Contact sites between ER and mitochondria are suspected to play a similar role in phospholipid trafficking as in yeast, but this has never been demonstrated. In contrast, it has been shown that plastids are able to transfer lipids to mitochondria during phosphate starvation. However, the proteins involved in such transfer are still unknown. Here, we identified in Arabidopsis thaliana a large lipid-enriched complex called the mitochondrial transmembrane lipoprotein (MTL) complex. The MTL complex contains proteins located in the two mitochondrial membranes and conserved in all eukaryotic cells, such as the TOM complex and AtMic60, a component of the MICOS complex. We demonstrate that AtMic60 contributes to the export of phosphatidylethanolamine from mitochondria and the import of galactoglycerolipids from plastids during phosphate starvation. Furthermore, AtMic60 promotes lipid desorption from membranes, likely as an initial step for lipid transfer, and binds to Tom40, suggesting that AtMic60 could regulate the tethering between the inner and outer membranes of mitochondria.
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS-CEA-INRA-Université Grenoble Alpes, 38000 Grenoble, France. Electronic address: morganemichaud71@gmail.com.
authors.forename: Morgane
authors.initials: M
authors.lastname: Michaud
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS-CEA-INRA-Université Grenoble Alpes, 38000 Grenoble, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Gros
authors.affiliation: Laboratoire de Biologie à Grande Echelle, U1038 CEA-INSERM-Université Grenoble Alpes, 38000 Grenoble, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Tardif
authors.affiliation: Laboratoire de Biologie à Grande Echelle, U1038 CEA-INSERM-Université Grenoble Alpes, 38000 Grenoble, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Brugière
authors.affiliation: Laboratoire de Biologie à Grande Echelle, U1038 CEA-INSERM-Université Grenoble Alpes, 38000 Grenoble, France.
authors.forename: Myriam
authors.initials: M
authors.lastname: Ferro
authors.affiliation: Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
authors.forename: William A
authors.initials: WA
authors.lastname: Prinz
authors.affiliation: Laboratory of Cell and Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892, USA.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Toulmay
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Jaideep
authors.initials: J
authors.lastname: Mathur
authors.affiliation: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G 2W1, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Wozny
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS-CEA-INRA-Université Grenoble Alpes, 38000 Grenoble, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Falconet
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS-CEA-INRA-Université Grenoble Alpes, 38000 Grenoble, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Maréchal
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS-CEA-INRA-Université Grenoble Alpes, 38000 Grenoble, France.
authors.forename: Maryse A
authors.initials: MA
authors.lastname: Block
authors.affiliation: Laboratoire de Physiologie Cellulaire et Végétale, UMR 5168 CNRS-CEA-INRA-Université Grenoble Alpes, 38000 Grenoble, France. Electronic address: juliette.jouhet@cea.fr.
authors.forename: Juliette
authors.initials: J
authors.lastname: Jouhet
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D050356:Lipid Metabolism; D008928:Mitochondria / Q000378:metabolism*; D033681:Mitochondrial Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D021381:Protein Transport
chemical_list: D029681:Arabidopsis Proteins; C000612650:Mic60 protein, Arabidopsis; D033681:Mitochondrial Membrane Transport Proteins; C000612651:Tom40 protein, Arabidopsis