What is the connection between mitochondria and apoptosis? Mitochondria play a crucial role in apoptosis, which is a programmed cell death mechanism responsible for maintaining tissue homeostasis and eliminating unwanted or damaged cells. Mitochondria contain several pro-apoptotic proteins such as cytochrome c and caspases that are released into the cytosol and initiate the apoptotic cascade. The mitochondrial electron transport chain (ETC) plays a key role in maintaining the integrity of mitochondria and regulating apoptosis. When a cell is stressed, the ETC can become dysfunctional, leading to the production of reactive oxygen species (ROS) and the opening of mitochondrial permeability transition pores (mPTP). This results in the release of cytochrome c into the cytosol, which activates caspase cascades and initiates apoptosis. Additionally, the mitochondrial fission and fusion machinery is also critical in determining the fate of the cell. Excessive fusion can prevent apoptosis, while excessive fission can induce it. Mitochondrial fission and fusion are regulated by several proteins, including dynamin-related protein 1 (DRP1) and mitofusin 1 and 2 (MFN1/2). Overall, mitochondria play a crucial role in the initiation and regulation of apoptosis, and dysregulation of mitochondrial function can lead to various diseases such as cancer and neurodegeneration. References: 1. Green, D. R., & Kroemer, G. (2004). The pathophysiology of mitochondrial cell death. Science, 305(5684), 626-629. 2. Youle, R. J., & van der Bliek, A. M. (2012). Mitochondrial fission, fusion, and stress. Science, 337(6098), 1062-1065. 3. Wang, C., Youle, R. J., & Theissen, N. C. (2016). The role of mitochondria in apoptosis. Annual review of genetics, 50, 439-465.
