Atg32 is a tag for mitochondria degradation in yeast.

The elimination of aged, damaged, or excess mitochondria is an important subcellular event to maintain proper cellular homeostasis. Recent studies reveal that autophagy-dependent degradation of mitochondria (mitophagy) plays an important role in removing these organelles. Very little is known, however, about the molecular mechanism of mitophagy. We found a novel protein, Atg32, that is required for mitophagy but not for other types of selective autophagy or nonselective autophagy. Atg32 is a mitochondrial outer membrane protein. When mitophagy is induced, Atg32 binds to Atg11, an adaptor protein for selective autophagy. Eventually, this interaction results in the recruitment of mitochondria to the vacuole for degradation.