Use of a live cell microscopy approach to compare the response of the PINK1:Parkin mitophagy pathway to different mitochondrial depolarization agents

Abstract

The PINK1:Parkin pathway regulates mitochondrial network health by facilitating the autophagic destruction of damaged or dysfunctional mitochondria. While this pathway is widely studied, it remains unclear how it responds to recurring or partial losses of mitochondrial membrane potential. Here we show that PINK1 is capable of a rapid response to fluctuations in mitochondrial membrane potential. Parkin, using phospho-ubiquitin as a docking site, serves as a marker of previous mitochondrial stress and can accumulate over time so long as its ubiquitin ligase activity is conserved. The two different time scales on which these proteins operate ensure immediate responses to MMP fluctuations and incorporation of mitochondrial stress over time.