Mitochondria serve various cellular functions including calcium homeostasis, lipid modification, energy production, triggering apoptosis. They are highly dynamic organelles that continuously divide or fuse to form small isolated units or elaborate interconnected networks within cells. Whereas fragmented mitochondria function in apoptosis, the cellular roles of filamentous mitochondria are still unknown. We are using live cell imaging approaches to investigate mitochondrial dynamism in the context of the cell cycle and to determine whether this is linked to changes in energy production or other features of the cell cycle. Using an RFP-tagged mitochondrial marker to visualize mitochondria at different cell cycle stages, we have determined that mitochondrial morphology is highly regulated during the cell cycle. At one extreme are mitochondria in mitotic cells, in which mitochondria consist of hundreds of small fragments scattered throughout the cytoplasm. At the other extreme are mitochondria in cells at G1/S, in which the organelles appear as a single continuous network. We are currently investigating the role of these cell cycle-dependent mitochondrial morphologies in the context of cell cycle progression.
Studies conducted by Kasturi Mitra.