Elena Rugarli1, Aleksandra Trifunovic2. 1. Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, D-50931 Cologne, Germany; Institute for Genetics, University of Cologne, D-50674 Cologne, Germany. Electronic address: elena.rugarli@uni-koeln.de. 2. Cologne Excellence Cluster on Cellular Stress Responses in Ageing-Associated Diseases (CECAD), University of Cologne, D-50931 Cologne, Germany; Institute for Mitochondrial Diseases and Ageing, Medical Faculty, University of Cologne, D-50931 Cologne, Germany. Electronic address: aleksandra.trifunovic@uk-koeln.de.