Figure 1 | Cell Death & Differentiation

Figure 1

From: The late stages of autophagy: how does the end begin?

Figure 1

Schematic diagram of autophagy and the LC3 reaction pathway. (a) Representative stages of autophagy. The isolation membrane/phagophore traps a portion of cytosol and becomes an autophagosome. The autophagosome fuses with the lysosome to become an autolysosome and its contents are degraded. (b) The LC3 reaction pathway. LC3 translated from mRNA is called pro-LC3 and possesses an unnecessary C-terminal tail. Subsequently, Atg4 protease cleaves the tail sequence to generate form-I LC3, which has a C-terminal glycine. Form-I LC3 is activated by Atg7 (E1) to become a high-energy thio-ester intermediate conjugated to Atg3 (E2) enzyme. Atg3-LC3 conjugate is recruited to the site where lipidation occurs by directly binding to Atg16L complex, and the C-terminus of LC3 forms an amino bond to the head group of phosphatidylethanolamine (PE), generating form-II. Form-II LC3 becomes membrane bound. Form-II LC3 is then cleaved at the PE by Atg4 to regenerate form-I

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