Capacity Bio

Mitophagy is the evolutionarily conserved process by which dysfunctional mitochondria are tagged, removed, and replaced in cells. Mitochondria are dynamic organelles that undergo constant cycles of fission (division of one mitochondria) and fusion (combining of two mitochondria). In a healthy cell, this process helps to segregate old, dysfunctional mitochondria from functional ones. Dysfunctional mitochondria are tagged for degradation and recycling. Engulfment of tagged mitochondria by an autophagosome and subsequent fusion with an acidic lysosome leads to activation of enzymes that break down and recycle the mitochondria. Importantly, removal of mitochondria by mitophagy triggers mitochondrial biogenesis and maintenance of the optimal mitochondrial mass specific for each cell type. During aging or disease, the ability of the cell to identify or process dysfunctional mitochondria is deficient. The accumulation of energetically suboptimal mitochondria inside each cell leads to release of reactive oxygen species (ROS) and inflammatory signals such as cytochrome c and mtDNA, calcium dysregulation, decreased ATP production, and cell death.