Novel factors involved in ribosome maturation and translation in mitochondria.

Mitochondria are double membrane bound cell organelles that host many catabolic and anabolic pathways of intermediary and energy metabolism, as well as participate in processes of cell signaling, aging and cell death. These organelles maintain a small genome and a protein synthesis machinery. According to recent estimates, healthy yeast and human mitochondria harbor approximately 1200 and 1800 proteins, respectively. However, it has been predicted that many additional mitochondrial proteins are yet to be identified.

In this study, we have significantly expanded the potential mitochondrial proteome in yeast by using advanced bioinformatic tools as well as biological experiments. Many of these newly identified proteins are likely to have important physiological functions. A subset of these proteins is predicted to be required for the maturation of mitochondrial ribosomes which carry out protein synthesis.

I have performed a more detailed characterization of the yeast mitochondrial ribosomal protein Rsm22, a factor also conserved in mouse and human. My bioinformatic and structural analyses revealed clues about the function of Rsm22. My functional analyses demonstrate that Rsm22 is essential for mitochondrial respiration, is able to methylate RNA and participates in the mitochondrial translation process, probably by (t)RNA methylation.