Research Klecker Group: The molecular details of mitochondrial inter-organelle interactions
Mitochondria originate from once free-living a-proteobacteria that were devoured from the most ancient common ancestor of today’s eukaryotes. Yet, once internalized, the bacterial feast was not digested but adopted as an integral part of the cell. During millions of years of evolution the prokaryotic symbionts lost their autonomy and became intracellular organelles that are dependent on the metabolic processes of the host cell: Although mitochondria nowadays still maintain their own genome and synthesize small fractions of their proteome, the vast majority of all mitochondrial proteins are encoded in the nuclear DNA and imported from the cytosol. Likewise, the lipids that build both mitochondrial membranes are either synthesized in mitochondria from imported precursors or directly obtained from other organelles by non-vesicular lipid-transport-processes. Mitochondria play a crucial role in the cellular physiology and, hence, are found in virtually all eukaryotes. They are most famous for their central role in energy generation as they harbor the components of the respiratory chain. Besides that, mitochondria partake in intracellular signaling, regulated cell death, and several metabolic pathways, such as the Krebs cycle, the assembly of Fe/S clusters and the biosynthesis of certain phospholipids. Many of the various pathways that mitochondria participate in require the joint action of two or more organelles. Thus, whilst mitochondria adapted to their new environment inside of the host cell, they faced the challenge to establish functional and physical connections to their neighboring subcellular compartments.
We utilize the power of baker’s yeast as a model system to study inter-organelle interactions with a strong focus on mitochondria. We exploit state-of-the-art genetic and microscopy approaches to study the molecular machineries that establish physical inter-organelle connections, the cellular processes that are integrated into the regulation of contact site formation, and the molecular players that mediate signaling between physically connected organelles. ...more