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Updated: Mar 2, 2026

Visualizing Mitophagy with Fluorescent Dyes for Mitochondria and Lysosome
Published on: November 30, 2022
How autophagy eats large mitochondria: Autophagosome formation coupled with mitochondrial fragmentation
Shun-Ichi Yamashita1, Tomotake Kanki1
1a Department of Cellular Physiology , Niigata University Graduate School of Medical and Dental Sciences , Niigata , Japan.
Abstract:
Mitochondrial autophagy (mitophagy) is thought to be a multi-step pathway wherein mitochondria are first divided into small fragments, which are subsequently recognized by the phagophore. DNM1L (dynamin 1 like) plays a pivotal role in mitochondrial division; however, its role in mitophagy remains controversial. In our recent study, we examined the contribution of DNM1L to mitophagy and showed that mitophagy and mitochondrial division occur even in DNM1L-defective cells. Furthermore, time-lapse imaging of mitophagy showed that DNM1L-independent mitochondrial division occurs concomitantly with autophagosome formation. Upstream factors of autophagosome formation, i.e., RB1CC1/FIP200, ATG14, and WIPIs, are required for mitochondrial division, whereas ATG5 and ATG3 are dispensable. These results indicate that a portion of the tubular mitochondria is first recognized and then divided into small fragments by a phagophore-mediated event, independently of DNM1L. This autophagic process suggests that autophagy has the potential to degrade substrates larger than autophagosomes.
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