Periodic Reporting for period 3 - MitoCRISTAE (Mitochondrial Cristae Biogenesis)
Reporting period: 2022-10-01 to 2024-03-31
All the cells of the body require energy to do their jobs. Mitochondria, organelles found abundantly in every cell, are the so-called powerhouses. They produce a molecule that releases the energy required to support cellular functions. Mitochondrial dysfunction is associated with many varied diseases and conditions. MitoCRISTAE is applying new high-tech methods to study the development of the convoluted inner membrane of mitochondria, whose dynamically changing structure has been linked to the functioning of the energy production pathway. The infoldings of the inner membrane are denoted cristae. MitoCRISTAE aims at investigating the molecular pathways that determine cristae biogenesis in cells. Thereby, in studies only recently possible, the team plans the pioneering investigation of membrane development over time to understand mitochondrial structure and function in health and disease.
In the period covered by the report, the team has established a number of imaging methods to visualize mitochondrial cristae in living and fixed cells, using super-resolution light microscopy and electron microscopy. By creating a large number of genetically modified cell lines lacking proteins that are required for the generation and/or maintenance of cristae they have prepared the basis for detailed experiments to investigate the function of proteins involved in cristae biogenesis or causing diseases in human patients. Notably, they report on the effects of re-expression of the mitochondrial proteins Mic10 and Mic60 in Mic10 and Mic60 deficient cells, respectively. They showed substantial membrane rearrangements as well as pronounced re-distributions of numerous inner membrane proteins upon the reappearance of a proper mitochondrial architecture. These results demonstrate the interplay of numerous factors to ensure proper cristae biogenesis. For these studies they relied on several state-of-the-art imaging methodologies, including the first demonstrations of MINFLUX nanoscopy on mitochondria.
In the first funding period, the team has been able to visualize the re-appearance of cristae in mitochondria initially lacking a protein required for proper mitochondrial architecture using live-cell super-resolution light microscopy and 3D electron microscopy. These data provide novel insights into the dynamics of the mitochondrial inner membrane. Using MINFLUX and MINSTED super-resolution microscopy they localized proteins with unprecedented localization precisions. The team expects to generate detailed knowledge of how mitochondrial ultrastructure in healthy and diseased cells is generated and maintained. The findings might spark innovative and novel strategies for the treatment of devastating human mitochondria related diseases.