Apobec2 deficiency causes mitochondrial defects and mitophagy in skeletal muscle

Yusuke Sato, Hideaki Ohtsubo, Naohiro Nihei, Takane Kaneko, Yoriko Sato, Shin Ichi Adachi, Shinji Kondo, Mako Nakamura, Wataru Mizunoya, Hiroshi Iida, Ryuichi Tatsumi, Cristina Rada, Fumiaki Yoshizawa

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


Apobec2 is a member of the activation-induced deaminase/apolipoprotein B mRNA editing enzyme catalytic polypeptide cytidine deaminase family expressed in differentiated skeletal and cardiac muscle. We previously reported that Apobec2 deficiency in mice leads to a shift in muscle fiber type, myopathy, and diminished muscle mass. However, the mechanisms ofmyopathy caused by Apobec2 deficiency and its physiologic functions are unclear. Here we show that, although Apobec2 localizes to the sarcomeric Z-lines in mouse tissue and cultured myotubes, the sarcomeric structure is not affected in Apobec2-deficient muscle. In contrast, electron microscopy reveals enlarged mitochondria and mitochondria engulfed by autophagic vacuoles, suggesting that Apobec2 deficiency causes mitochondrial defects leading to increased mitophagy in skeletal muscle. Indeed, Apobec2 deficiency results in increased reactive oxygen species generation and depolarized mitochondria, leading to mitophagy as a defensive response. Furthermore, the exercise capacity of Apobec2-/- mice is impaired, implying Apobec2 deficiency results in ongoing muscle dysfunction. The presence of rimmed vacuoles in myofibers from 10-mo-old mice suggests that the chronic muscle damage impairs normal autophagy. We conclude that Apobec2 deficiency causes mitochondrial defects that increase muscle mitophagy, leading to myopathy and atrophy. Our findings demonstrate that Apobec2 is required for mitochondrial homeostasis to maintain normal skeletal muscle function.

Original languageEnglish
Pages (from-to)1428-1439
Number of pages12
JournalFASEB Journal
Issue number3
Publication statusPublished - Mar 2018

All Science Journal Classification (ASJC) codes

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics


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