Investigation for regulatory mechanisms of cnidarian muscle contraction

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K06755
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 44050:Animal physiological chemistry, physiology and behavioral biology-related
• Research Institution: Hokkaido University
• Principal Investigator: Tanaka Hiroyuki 北海道大学, 水産科学研究院, 助教 (90241372)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 筋肉 / 刺胞動物 / カルシウムイオン / ミオシン / 筋収縮調節 / リン酸化 / トロポミオシン

Outline of Final Research Achievements

It was suggested that there should be a novel Ca-regulatory mechanism of muscular contraction, which includes the Ca-dependent interaction between Ser/Thr-kinase and myosin in cnidarian striated muscle. We also characterized other muscular proteins purified from moon jelly. Especially, we found a novel Ca-binding protein, AaCBP, specific for the striated musculature, though its participation in the regulation could not be determined. We also revealed the tissue-specific expression of four tropomyosin isoforms. The jellyfish tropomyosin activated the Mg-ATPase activity of reconstituted actomyosin, in contrast to those from other animal species are known to inhibit the activity.

Free Research Field

海洋応用生命科学

Academic Significance and Societal Importance of the Research Achievements

刺胞動物は動物進化のごく初期の段階で初めて神経と筋肉を獲得したとされる。刺胞動物の筋肉の収縮は高等動物と同様にATP分解に共役したアクチンとミオシンの相互作用によっているが、それを刺激に応じて調節する分子レベルの機構が不明だった。本研究では、ミズクラゲの筋肉を材料に実験を行い、横紋筋に存在するキナーゼの一種が細胞内Caイオン濃度依存的にミオシンに結合・解離してアクチンとミオシンの相互作用を調節するという新規の筋収縮調節機構の存在を提唱した。