Poster Presentation HUPO 2019 - 18th Human Proteome Organization World Congress

The dynamic mitochondrial complexome (#562)

Juliana Heidler 1 , Heiko Giese 2 , Jana Meisterknecht 1 , Sarah Stenton 3 4 , Holger Prokisch 3 4 , Ilka Wittig 1
  1. ZBC - Functional Proteomics, Goethe University Frankfurt, Frankfurt/M., Germany
  2. Molecular Bioinformatics, Goethe University Frankfurt, Frankfurt/M., Germany
  3. Institute of Human Genetics, Technische Universität München, München, Germany
  4. Institute of Human Genetics, Helmholtz Zentrum München, München, Germany

Many patients with mitochondrial disorders suffer from impaired assembly of mitochondrial protein complexes due to defects in genes encoding assembly factors. The sequence of protein complex assembly was intensively studied in proliferating cells. These studies mostly reflect the de-novo assembly and give only limited information of the protein complex dynamics in differentiated cells and tissues. The combination of blue native electrophoresis with quantitative mass spectrometry identifies even scarce sub-complexes, assembly intermediates, and complex remodeling. In this study, we combined complexome profiling and pulse stable isotope labeling of amino acids in cell culture (Pulsed-SILAC) to study the turnover and half-life of single proteins within protein complexes in differentiated post-mitotic C2C12-myotubes. The results represent a comprehensive data collection of dynamics in all mitochondrial protein complexes. Complete replacement e.g. for all protein complexes from the oxidative phosphorylation system requires about a month. We detected higher turnover rates between interface subunits of dimeric and oligomeric ATP synthase and supercomplexes suggesting more dynamics between as within complexes. In detail, we identified subunits of complex I with higher turnover rates in the parts of electron transport modules, suggesting quality control and repairing mechanisms within assembled complexes to ensure full bioenergetics function in differentiated cells. Application of the developed method to patients with a mitochondrial disorder discovered a novel factor involved in quality control and repair of complex I.