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Hokkaido University Collection of Scholarly and Academic Papers >
Graduate School of Agriculture / Faculty of Agriculture >
Peer-reviewed Journal Articles, etc >
The ubiquitin ligase Ozz decreases the replacement rate of embryonic myosin in myofibrils
This item is licensed under:Creative Commons Attribution 4.0 International
| Title: | The ubiquitin ligase Ozz decreases the replacement rate of embryonic myosin in myofibrils |
| Authors: | Ichimura, Emi Browse this author | | Ojima, Koichi Browse this author | | Muroya, Susumu Browse this author | | Suzuki, Takahiro Browse this author | | Kobayashi, Ken Browse this author →KAKEN DB | | Nishimura, Takanori Browse this author →KAKEN DB |
| Keywords: | myofibril | | myosin | | skeletal muscle | | thick filament | | ubiquitin ligase | | ubiquitin-proteasome system |
| Issue Date: | Sep-2021 |
| Publisher: | John Wiley & Sons |
| Journal Title: | Physiological reports |
| Volume: | 9 |
| Issue: | 17 |
| Start Page: | e15003 |
| Publisher DOI: | 10.14814/phy2.15003 |
| Abstract: | Myosin, the most abundant myofibrillar protein in skeletal muscle, functions as a motor protein in muscle contraction. Myosin polymerizes into the thick filaments in the sarcomere where approximately 50% of embryonic myosin (Myh3) are replaced within 3 h (Ojima K, Ichimura E, Yasukawa Y, Wakamatsu J, Nishimura T, Am J Physiol Cell Physiol 309: C669-C679, 2015). The sarcomere structure including the thick filament is maintained by a balance between protein biosynthesis and degradation. However, the involvement of a protein degradation system in the myosin replacement process remains unclear. Here, we show that the muscle-specific ubiquitin ligase Ozz regulates replacement rate of Myh3. To examine the direct effect of Ozz on myosin replacement, eGFP-Myh3 replacement rate was measured in myotubes overexpressing Ozz by fluorescence recovery after photobleaching. Ozz overexpression significantly decreased the replacement rate of eGFP-Myh3 in the myofibrils, whereas it had no effect on other myosin isoforms. It is likely that ectopic Ozz promoted myosin degradation through increment of ubiquitinated myosin, and decreased myosin supply for replacement, thereby reducing myosin replacement rate. Intriguingly, treatment with a proteasome inhibitor MG132 also decreased myosin replacement rate, although MG132 enhanced the accumulation of ubiquitinated myosin in the cytosol where replaceable myosin is pooled, suggesting that ubiquitinated myosin is not replaced by myosin in the myofibril. Collectively, our findings showed that Myh3 replacement rate was reduced in the presence of overexpressed Ozz probably through enhanced ubiquitination and degradation of Myh3 by Ozz. |
| Rights: | http://creativecommons.org/licenses/by/4.0/ |
| Type: | article |
| URI: | http://hdl.handle.net/2115/82933 |
| Appears in Collections: | 農学院・農学研究院 (Graduate School of Agriculture / Faculty of Agriculture) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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