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Updated: Jun 16, 2026

Exploring the Regulation of Lipid Droplet Catabolism through Lipophagy
Published on: January 31, 2025
Autophagy takes an alternative pathway
Shigeomi Shimizu1, Satoko Arakawa, Yuya Nishida
1Department of Pathological Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan. shimizu.pcb@mri.tmd.ac.jp
Abstract:
ATG5 and ATG7 are considered as essential molecules for induction of macroautophagy. However, we found that cells lacking ATG5 or ATG7 can still form autophagosomes/autolysosomes and perform autophagy-mediated protein degradation when subjected to certain stresses. Although lipidation of LC3 is accepted to be a good indicator of macroautophagy, it did not occur during the ATG5/ATG7-independent alternative macroautophagy. Unlike conventional macroautophagy, autophagosomes seemed to be generated in a Rab9-dependent manner by the fusion of the phagophore with vesicles derived from the trans-Golgi and late endosomes. Mammalian macroautophagy can occur via at least two different pathways, which are an ATG5/ATG7-dependent conventional pathway and an ATG5/ATG7-independent alternative pathway.
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