[Protein degradation by autophagy].
Long-lived and structural proteins that become old and unneeded are degraded by the autophagy-lysosomal system. In mammalian cells, such proteins, together with part of the cytoplasm, are sequestered by the endoplasmic reticulum- like isolation membrane, resulting in the formation of autophagic vacuoles/autophagosomes. These nascent autophagic vacuoles receive lysosomal enzymes by fusing with transporting vesicles from the trans-Golgi network or lysosomes, and they become autolysosomes that start to degrade the enwrapped materials. In the cells that are unable to perform autophagy since they lackessential autophagy machineries such as Atg5 and Atg7, ubiquitin aggregates and unneeded and old organelles are stored in the cytoplasm. Moreover, in the cells that lacklysosomal proteinases undegraded substrates are stored in lysosomes, resulting in lysosomal storage disorder. Such cells undergo cell death.
Uchiyama
Yasuo
Y
Department of Cell Biology and Neuroscience, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita Osaka 565-0871, Japan.
D000818:Animals; D001343:Autophagy; D006801:Humans; D016464:Lysosomal Storage Diseases / Q000201:enzymology; D008247:Lysosomes / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*
D011506:Proteins; D010447:Peptide Hydrolases