| Popis: |
The mitochondrion is a complex, double membrane organelle that serves several important cellular functions including ATP synthesis, Ca 2+ buffering, and ROS homeostasis. Although classic mitochondrial diagrams depict the mitochondrion as a simple oval or “bean” shaped organelle, the mitochondria can form extensive tubular networks or numerous small spheres in response to various cellular environments through two opposing processes, mitochondrial fission and fusion. Deregulation of mitochondrial dynamics has been implicated in a wide range of diseases, including Parkinson’s disease, heart disease and cancer. While significant emphasis for the last 15 years has been placed on the identification of the protein machinery responsible regulating mitochondrial morphology, it remains less clear how mitochondrial morphology affects various cellular functions and cellular fate outcomes. This thesis summarizes our findings on how mitochondrial morphology regulates cellular fate in the context of mitotic cell division and apoptosis. Using live cell microscopy and image analysis software we characterized mitochondrial dynamics with single cell resolution. We found that loss of key components of the mitochondrial fission machinery promotes a defect in cell cycle progression, characterized by an inability for cells to exit G2/M. Prolonged periods of mitochondrial fusion induced potent cell death, suggesting a novel mechanism to target the replicative potential of cancer cells. We also found that mitochondrial fission and fusion can alter the kinetics of cell death following apoptotic stimuli by inducing mitochondrial fusion prior to the commitment step in apoptosis, mitochondrial membrane permeabilization. This thesis summarizes our work in trying to elucidate how the structure of the mitochondria influences both mitochondrial and cellular fate. |
