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. Author manuscript; available in PMC: 2008 Dec 12.
Published in final edited form as: Apoptosis. 2008 Jan;13(1):1–9. doi: 10.1007/s10495-007-0154-9

Figure 1. Schematic of macroautophagy.

Figure 1

A membrane forms and expands to sequester cytoplasm and organelles in a double-membrane autophagosome. The initial step requires the activity of a Type III PI3kinase and the Beclin1 protein and is regulated by diverse signaling pathways providing both positive and negative signals. Completion and expansion of the autophagosome requires the products of two protein conjugation systems that produce Atg5-Atg12 and Atg8/LC3-PE. The mature autophagosome fuses with a lysosome through a step that requires the Rab7 GTPase and the LAMP2 protein to produce the autophagolysosome in which the contents are degraded.