[PDF][PDF] Mitochondrial stasis reveals p62-mediated ubiquitination in parkin-independent mitophagy and mitigates nonalcoholic fatty liver disease

T Yamada, D Murata, Y Adachi, K Itoh, S Kameoka… - Cell metabolism, 2018 - cell.com
T Yamada, D Murata, Y Adachi, K Itoh, S Kameoka, A Igarashi, T Kato, Y Araki, RL Huganir
Cell metabolism, 2018cell.com
It is unknown what occurs if both mitochondrial division and fusion are completely blocked.
Here, we introduced mitochondrial stasis by deleting two dynamin-related GTPases for
division (Drp1) and fusion (Opa1) in livers. Mitochondrial stasis rescues liver damage and
hypotrophy caused by the single knockout (KO). At the cellular level, mitochondrial stasis re-
establishes mitochondrial size and rescues mitophagy defects caused by division
deficiency. Using Drp1KO livers, we found that the autophagy adaptor protein …
Summary
It is unknown what occurs if both mitochondrial division and fusion are completely blocked. Here, we introduced mitochondrial stasis by deleting two dynamin-related GTPases for division (Drp1) and fusion (Opa1) in livers. Mitochondrial stasis rescues liver damage and hypotrophy caused by the single knockout (KO). At the cellular level, mitochondrial stasis re-establishes mitochondrial size and rescues mitophagy defects caused by division deficiency. Using Drp1KO livers, we found that the autophagy adaptor protein p62/sequestosome-1—which is thought to function downstream of ubiquitination—promotes mitochondrial ubiquitination. p62 recruits two subunits of a cullin-RING ubiquitin E3 ligase complex, Keap1 and Rbx1, to mitochondria. Resembling Drp1KO, diet-induced nonalcoholic fatty livers enlarge mitochondria and accumulate mitophagy intermediates. Resembling Drp1Opa1KO, Opa1KO rescues liver damage in this disease model. Our data provide a new concept that mitochondrial stasis leads the spatial dimension of mitochondria to a stationary equilibrium and a new mechanism for mitochondrial ubiquitination in mitophagy.
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