Mitophagy is the selective degradation of mitochondria by autophagy. It often occurs to defective mitochondria following damage or stress.
Mitophagy is key in keeping the cell healthy. It promotes turnover of mitochondria and prevents accumulation of dysfunctional mitochondria which can lead to cellular degeneration. It is mediated by Atg32 (in yeast) and NIX and its regulator BNIP3 in mammals. Mitophagy is regulated by PINK1 and parkin proteins. In addition to the selective removal of damaged mitochondria, mitophagy is also required to adjust mitochondrial numbers to changing cellular metabolic needs, for steady-state mitochondrial turnover, and during certain cellular developmental stages, such as during cellular differentiation of red blood cells.