Autophagy is activated for cell survival after endoplasmic ReticulumStress

M Ogata, S Hino, A Saito, K Morikawa… - … and cellular biology, 2006 - Taylor & Francis
M Ogata, S Hino, A Saito, K Morikawa, S Kondo, S Kanemoto, T Murakami, M Taniguchi…
Molecular and cellular biology, 2006Taylor & Francis
Eukaryotic cells deal with accumulation of unfolded proteins in the endoplasmic reticulum
(ER) by the unfolded protein response, involving the induction of molecular chaperones,
translational attenuation, and ER-associated degradation, to prevent cell death. Here, we
found that the autophagy system is activated as a novel signaling pathway in response to
ER stress. Treatment of SK-N-SH neuroblastoma cells with ER stressors markedly induced
the formation of autophagosomes, which were recognized at the ultrastructural level. The …
Eukaryotic cells deal with accumulation of unfolded proteins in the endoplasmic reticulum (ER) by the unfolded protein response, involving the induction of molecular chaperones, translational attenuation, and ER-associated degradation, to prevent cell death. Here, we found that the autophagy system is activated as a novel signaling pathway in response to ER stress. Treatment of SK-N-SH neuroblastoma cells with ER stressors markedly induced the formation of autophagosomes, which were recognized at the ultrastructural level. The formation of green fluorescent protein (GFP)-LC3-labeled structures (GFP-LC3“ dots”), representing autophagosomes, was extensively induced in cells exposed to ER stress with conversion from LC3-I to LC3-II. In IRE1-deficient cells or cells treated with c-Jun N-terminal kinase (JNK) inhibitor, the autophagy induced by ER stress was inhibited, indicating that the IRE1-JNK pathway is required for autophagy activation after ER stress. In contrast, PERK-deficient cells and ATF6 knockdown cells showed that autophagy was induced after ER stress in a manner similar to the wild-type cells. Disturbance of autophagy rendered cells vulnerable to ER stress, suggesting that autophagy plays important roles in cell survival after ER stress.
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