Mitophagy is the process of selective mitochondrial degradation via autophagy, 
which has an important role in mitochondrial quality control. Very little is 
known, however, about the molecular mechanism of mitophagy. A genome-wide yeast 
mutant screen for mitophagy-defective strains identified 32 mutants with a block 
in mitophagy, in addition to the known autophagy-related (ATG) gene mutants. We 
further characterized one of these mutants, ylr356wDelta that corresponds to a 
gene whose function has not been identified. YLR356W is a mitophagy-specific 
gene that was not required for other types of selective autophagy or 
macroautophagy. The deletion of YLR356W partially inhibited mitophagy during 
starvation, whereas there was an almost complete inhibition at post-log phase. 
Accordingly, we have named this gene ATG33. The new mutants identified in this 
analysis will provide a useful foundation for researchers interested in the 
study of mitochondrial homeostasis and quality control.