title: Organization of Mitochondrial Gene Expression in Two Distinct Ribosome-Containing Assemblies.
abstract: Mitochondria contain their own genetic system that provides subunits of the complexes driving oxidative phosphorylation. A quarter of the mitochondrial proteome participates in gene expression, but how all these factors are orchestrated and spatially organized is currently unknown. Here, we established a method to purify and analyze native and intact complexes of mitochondrial ribosomes. Quantitative mass spectrometry revealed extensive interactions of ribosomes with factors involved in all the steps of posttranscriptional gene expression. These interactions result in large expressosome-like assemblies that we termed mitochondrial organization of gene expression (MIOREX) complexes. Superresolution microscopy revealed that most MIOREX complexes are evenly distributed throughout the mitochondrial network, whereas a subset is present as nucleoid-MIOREX complexes that unite the whole spectrum of organellar gene expression. Our work therefore provides a conceptual framework for the spatial organization of mitochondrial protein synthesis that likely developed to facilitate gene expression in the organelle.
authors: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden.
authors: Kirsten
authors: K
authors: Kehrein
authors: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden.
authors: Ramon
authors: R
authors: Schilling
authors: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden.
authors: Braulio Vargas
authors: BV
authors: Möller-Hergt
authors: Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37070 Göttingen, Germany.
authors: Christian A
authors: CA
authors: Wurm
authors: Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, 37070 Göttingen, Germany; Department of Neurology, University of Göttingen Medical School, 37073 Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), 37073 Göttingen, Germany.
authors: Stefan
authors: S
authors: Jakobs
authors: Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany.
authors: Tobias
authors: T
authors: Lamkemeyer
authors: Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, 50931 Cologne, Germany; Institute for Genetics, University of Cologne, 50931 Cologne, Germany; Center for Molecular Medicine (CMMC), University of Cologne, 50931 Cologne, Germany; Max-Planck-Institute for Biology of Aging, 50931 Cologne, Germany.
authors: Thomas
authors: T
authors: Langer
authors: Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, 106 91 Stockholm, Sweden. Electronic address: martin.ott@dbb.su.se.
authors: Martin
authors: M
authors: Ott