Investigation of Yeast Mitophagy with Fluorescence Microscopy and Western Blotting

Selective clearance of superfluous or dysfunctional mitochondria is a fundamental process that depends on the autophagic membrane trafficking pathways found in many cell types. This catabolic event, called mitophagy, is conserved from yeast to humans and serves to control mitochondrial quality and quantity. In budding yeast, degradation of mitochondria occurs under various physiological conditions, such as respiration at stationary phase, or starvation in a prolonged period. During these events, the transmembrane protein Atg32 localizes to the mitochondrial surface and plays a specific and essential role in yeast mitophagy. In this chapter, we describe methods to observe transport of mitochondria to the vacuole, a lytic compartment in yeast, using fluorescence microscopy, and semi-quantify the progression of Atg32-mediated mitophagy by Western blotting.