FIG. 1.

Models for macroautophagy, pexophagy, and the Cvt pathway in the yeast S. cerevisiae. The basic mechanism in macroautophagy, macropexophagy, and the Cvt pathway is the sequestration of cargo material (bulk cytoplasm, peroxisomes, or prApe1 and Ams1, respectively) by a cytosolic double-membrane vesicle. Upon completion, the sequestering vesicle docks with the vacuole and then fuses with it. In this way, the inner vesicle is liberated inside the vacuole, where it is finally consumed by hydrolases. In micropexophagy, sequestration occurs directly at the vacuole surface, again resulting in the release of a vesicle within the vacuolar lumen. The small circles representing prApe1 or Ams1 are monomeric forms, and the medium circles indicate the oligomeric forms of these hydrolases.