The Sodom and Gomorrah conundrum of yeast mitophagy

The physiological role of mitophagy in baker's yeast (Saccharomyces cerevisiae) is less clear than it is for mammalian systems. In this chapter, I aim to cover the known aspects of mitophagy in baker’s yeast with a special emphasis on the hypothesis that mitophagy occurs specifically on mitochondria with a distinct composition that is separated from the rest of the mitochondrial network by an active segregation process. The underlying assumption behind this hypothesis is that in a homogeneous mitochondrial network, a metabolic crisis will occur simultaneously or near-simultaneously in all mitochondria, necessitating a molecular segregation process that keeps at least part of the network “healthy” at a steady state. A simple percolation/distillation mechanism for the generation of mitochondrial heterogeneity is proposed, and data supporting this hypothesis are discussed alongside parallel phenomena from mammalian systems.