Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
Sabine Poerschke
Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
Silke Oeljeklaus
Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
Cong Wang
Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
Ricarda Richter-Dennerlein
Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
Johannes Sattmann
Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
Diana Bauermeister
Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
Elisa Hanitsch
Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany
Stefan Stoldt
Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany; Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
Thomas Langer
Department of Mitochondrial Proteostasis, Max Planck Institute for Biology of Ageing, Cologne, Germany
Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany; Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany; Department of Neurology, University Medical Center Göttingen, Göttingen, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Translational Neuroinflammation and Automated Microscopy, Göttingen, Germany
Biochemistry and Functional Proteomics, Institute of Biology II, University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany
Department of Cellular Biochemistry, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany; Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Translational Neuroinflammation and Automated Microscopy, Göttingen, Germany; Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
Human mitochondria express a genome that encodes thirteen core subunits of the oxidative phosphorylation system (OXPHOS). These proteins insert into the inner membrane co-translationally. Therefore, mitochondrial ribosomes engage with the OXA1L-insertase and membrane-associated proteins, which support membrane insertion of translation products and early assembly steps into OXPHOS complexes. To identify ribosome-associated biogenesis factors for the OXPHOS system, we purified ribosomes and associated proteins from mitochondria. We identified TMEM223 as a ribosome-associated protein involved in complex IV biogenesis. TMEM223 stimulates the translation of COX1 mRNA and is a constituent of early COX1 assembly intermediates. Moreover, we show that SMIM4 together with C12ORF73 interacts with newly synthesized cytochrome b to support initial steps of complex III biogenesis in complex with UQCC1 and UQCC2. Our analyses define the interactome of the human mitochondrial ribosome and reveal novel assembly factors for complex III and IV biogenesis that link early assembly stages to the translation machinery.
