Abstract:
:In response to stress conditions (such as nutrient limitation or accumulation of damaged organelles) and certain pathological situations, eukaryotic cells use autophagy as a survival mechanism. During nutrient stress the main purpose of autophagy is to degrade cytoplasmic materials within the lysosome/vacuole lumen and generate an internal nutrient pool that is recycled back to the cytosol. This study elucidates a molecular mechanism for linking the degradative and recycling roles of autophagy. We show that in contrast to published studies, Atg22 is not directly required for the breakdown of autophagic bodies within the lysosome/vacuole. Instead, we demonstrate that Atg22, Avt3, and Avt4 are partially redundant vacuolar effluxers, which mediate the efflux of leucine and other amino acids resulting from autophagic degradation. The release of autophagic amino acids allows the maintenance of protein synthesis and viability during nitrogen starvation. We propose a "recycling" model that includes the efflux of macromolecules from the lysosome/vacuole as the final step of autophagy.
journal_name
Mol Biol Celljournal_title
Molecular biology of the cellauthors
Yang Z,Huang J,Geng J,Nair U,Klionsky DJdoi
10.1091/mbc.e06-06-0479subject
Has Abstractpub_date
2006-12-01 00:00:00pages
5094-104issue
12eissn
1059-1524issn
1939-4586pii
E06-06-0479journal_volume
17pub_type
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