Autophagy is a pathway involved in a wide array of cellular processes including development, aging, and immunity. It is evolutionarily conserved and ubiquitous among eukaryotic cells. In higher eukaryotes, autophagic dysfunction has been associated with tumor progression, heart disease and certain neurodegenerative disorders. One of the most distinguishing features of autophagy is the dynamic rearrangement of cellular membrane to sequester cytosol and organelles for delivery to the lysosome or vacuole. In recent years, morphological, genetic, biochemical and cell biological approaches have begun to provide insight into the molecular mechanisms underlying autophagy.

Degradation of peroxisomes (blue) by the vacuole (red) in the yeast Pichia pastoris

Autophagosomes (arrow) in the vacuole in the yeast, Saccharomyces cerevisiae, during nitrogen starvation

Autophagosomes (arrow) in the hypodermis in the nematode Caenorrhabditis elegans, during dauer developmental arrest