Mitochondria are central to energy production, metabolism, signaling, and cellular homeostasis in eukaryotic cells. Because mitochondria cannot be generated de novo,
they are propagated through growth and division of pre-existing mitochondria. Since most mitochondrial proteins and lipids are supplied from outside mitochondria,
mitochondrial expansion requires the continuous supply of newly synthesized proteins and lipids, mediated by protein translocators and the lipid transfer systems, respectively.
In contrast, a limited set of proteins is encoded by the mitochondrial genome and synthesized within mitochondria, while certain lipids, including cardiolipin and
phosphatidylethanolamine, are synthesized within mitochondria for imported precursors.
Thus, the coordinated assembly of mitochondrial proteins and lipids produced both within and outside mitochondria is essential for mitochondrial biogenesis and proliferation.
To maintain mitochondrial function, mitochondrial proteins are constantly monitored for their quality, and dysfunctional or mislocalized mitochondrial proteins are properly recognized and eliminated or rerouted. These quality control systems include recently identified protein extractases operating in mitochondria, the ER, and peroxisomes, which contribute to maintaining proper protein distribution among organelles. Recent studies have also revealed roles for mitochondrial RNA import and the escape of mitochondrial DNA from mitochondria in mitochondrial proteostasis and cellular homeostasis.
In this seminar, I will present and discuss recent findings from our lab on these topics, with a particular focus on how the trafficking of proteins lipids, and nucleic acid
contributes to mitochondrial biogenesis, quality control, and cellular homeostasis.
