An evidence based hypothesis on the existence of two pathways of mitochondrial crista formation
Max E Harner,
Ann-Katrin Unger,
Willie JC Geerts,
Muriel Mari,
Toshiaki Izawa,
Maria Stenger,
Stefan Geimer,
Fulvio Reggiori,
Benedikt Westermann,
Walter Neupert
Affiliations
Max E Harner
Max Planck Institute of Biochemistry, Martinsried, Germany; Walter Brendel Centre of Experimental Medicine, Ludwig-Maximilians-Universität München, Martinsried, Germany
Ann-Katrin Unger
Cell Biology and Electron Microscopy, Universität Bayreuth, Bayreuth, Germany
Willie JC Geerts
Biomolecular Imaging, Bijvoet Center, Universiteit Utrecht, Utrecht, Netherlands
Muriel Mari
Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
Toshiaki Izawa
Max Planck Institute of Biochemistry, Martinsried, Germany
Maria Stenger
Cell Biology and Electron Microscopy, Universität Bayreuth, Bayreuth, Germany
Stefan Geimer
Cell Biology and Electron Microscopy, Universität Bayreuth, Bayreuth, Germany
Fulvio Reggiori
Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
Max Planck Institute of Biochemistry, Martinsried, Germany; Department of Anatomy and Cell Biology, Biomedical Center, Ludwig-Maximilians Universität München, Martinsried, Germany
Metabolic function and architecture of mitochondria are intimately linked. More than 60 years ago, cristae were discovered as characteristic elements of mitochondria that harbor the protein complexes of oxidative phosphorylation, but how cristae are formed, remained an open question. Here we present experimental results obtained with yeast that support a novel hypothesis on the existence of two molecular pathways that lead to the generation of lamellar and tubular cristae. Formation of lamellar cristae depends on the mitochondrial fusion machinery through a pathway that is required also for homeostasis of mitochondria and mitochondrial DNA. Tubular cristae are formed via invaginations of the inner boundary membrane by a pathway independent of the fusion machinery. Dimerization of the F1FO-ATP synthase and the presence of the MICOS complex are necessary for both pathways. The proposed hypothesis is suggested to apply also to higher eukaryotes, since the key components are conserved in structure and function throughout evolution.
