J. Kim et Dj. Klionsky, Autophagy, cytoplasm-to-vacuole targeting pathway, and pexophagy in yeast and mammalian cells, ANN R BIOCH, 69, 2000, pp. 303-342
The sequestration and delivery of cytoplasmic material to the yeast vacuole
and mammalian lysosome require the dynamic mobilization of cellular membra
nes and specialized protein machinery. Under nutrient deprivation condition
s, double-membrane vesicles form around bulk cytoplasmic cargo destined for
degradation and recycling in the vacuole/lysosome. A similar process funct
ions to remove excess organelles under vegetative conditions in which they
are no longer needed. Biochemical, morphological, and molecular genetic stu
dies in yeasts and mammalian cells have begun to elucidate the molecular de
tails of this autophagy process. In addition, the overlap of macroautophagy
with the process of pexophagy and with the biosynthetic cytoplasm-to-vacuo
le targeting pathway, which delivers the resident vacuolar hydrolase aminop
eptidase I, indicates that these three pathways are related mechanistically
. Identification and characterization of the autophagic/cytoplasm-to-vacuol
e protein-targeting components: have revealed the essential roles for vario
us functional classes of proteins, including a novel protein conjugation sy
stem and the machinery for vesicle formation and fusion.