The molecular machinery of autophagy: unanswered questions

Autophagy is a process in which cytosol and organelles are sequestered within double-membrane vesicles that deliver the contents to the lysosome/vacuole for degradation and recycling of the resulting macromolecules. It plays an important role in the cellular response to stress, is involved in various developmental pathways and functions in tumor suppression, resistance to pathogens and extension of lifespan. Conversely, autophagy may be associated with certain myopathies and neurodegenerative conditions. Substantial progress has been made in identifying the proteins required for autophagy and in understanding its molecular basis; however, many questions remain. For example, Tor is one of the key regulatory…