Autophagy in the Eukaryotic Cell

The major cellular pathways for protein and organelle turnover are autophagy and proteasome-mediated degradation. These processes are important to maintain a well-controlled balance between anabolism and catabolism in order to have normal cell growth and development. They play an essential role during starvation, cellular differentiation, cell death, and aging but also in preventing some types of cancer (59). These degradation pathways permit the cell to eliminate unwanted or unnecessary organelles and to recycle the components for reuse (54, 59). The lysosome or vacuole is the major catabolic factory in eukaryotic cells and contains a range of hydrolases capable of degrading all cellular constituents. Organelle turnover is accomplished exclusively at this location through a process of autophagy that is conserved among yeast, plant, and animal