Protein Aggregation, Proteasome Regulation Autophagy, and Autophagic Cell Death : (Essential Roles of Atg5 in Autophagic Cell Death)

다국어 초록 (Multilingual Abstract)

Autophagic cell death is characterized by the accumulation of vacuoles in physiological and pathological conditions. However, its molecular event is unknown. Here, we show that Atg5, which is known to function in autophagy, contributes to autophagic cell death by interacting with Fas-associated protein with death domain(FADD). Down-regulation of Atg5 expression in HeLa cells suppresses cell death and vacuole formation induced by IFN-g. Inversely, ectopic expression of Atg5 using adenoviral delivery induces autophagic cell death. Deletion mapping analysis indicates that pro-cell death activity resides in the C-terminus of Atg5. Cells harboring the accumulated vacuoles triggered by IFN-r or Atg5 expression become dead and vacuole formation precedes cell death. 3-methyladenine or expression of Atg5K130R mutant blocks both cell death and vacuole formation triggered by IFN-g, while zVAD-fmk inhibits only cell death but not vacuole formation. Atg5 interacts with FADD via death domain in vitro and in vivo and the Atg5-mediated cell death, but not vacuole formation, is blocked in FADD-deficient cells. These results suggest that Atg5 plays a crucial role in IFN-g-induced autophagic cell death by interacting with FADD. Further, screening and isolation of regulatory genes modulating autophagy and autophagic cell death will be discussed.