Regulation of muscle contraction by Ca<sup>2+</sup> and ADP: Focusing on the auto-oscillation (SPOC)

Shin'Ichi Ishiwata*, Yuta Shimamoto, Madoka Suzuki, Daisuke Sasaki

*この研究の対応する著者

研究成果: Conference contribution

13 被引用数 (Scopus)

抄録

A molecular motor in striated muscle, myosin II, is a non-processive motor that is unable to perform physiological functions as a single molecule and acts as an assembly of molecules. It is widely accepted that a myosin II motor is an independent force generator; the force generated at a steady state is usually considered to be a simple sum of those generated by each motor. This is the case at full activation (pCa <5 in the presence of MgATP); however, we found that the myosin II motors show cooperative functions, i.e., non-linear auto-oscillation, named SPOC (SPontaneous Oscillatory Contraction), when the activation level is intermediate between those of contraction and relaxation (that is, at the intermediate level of pCa, 5∼6, for cardiac muscle, or at the coexistence of MgATP, MgADP and inorganic phosphate (Pi) at higher pCa (>7) for both skeletal and cardiac muscles). Here, we summarize the characteristics of SPOC phenomena, especially focusing on the physiological significance of SPOC in cardiac muscle. We propose a new concept that the auto-oscillatory property, which is inherent to the contractile system of cardiac muscle, underlies the molecular mechanism of heartbeat. Additionally, we briefly describe the dynamic properties of the thin filaments, i.e., the Ca<sup>2+</sup>-dependent flexibility change of the thin filaments, which may be the basis for the SPOC phenomena. We also describe a newly developed experimental system named "bio-nanomuscle," in which tension is asserted on a single reconstituted thin filament by interacting with crossbridges in the A-band composed of the thick filament lattice. This newly devised hybrid system is expected to fill the gap between the single-molecule level and the muscle system.

本文言語English
ホスト出版物のタイトルAdvances in Experimental Medicine and Biology
出版社Springer New York
ページ341-358
ページ数18
592
ISBN(印刷版)9784431384519
DOI
出版ステータスPublished - 2007

出版物シリーズ

名前Advances in Experimental Medicine and Biology
592
ISSN(印刷版)00652598

ASJC Scopus subject areas

  • 生化学、遺伝学、分子生物学(全般)
  • 医学(全般)

フィンガープリント

「Regulation of muscle contraction by Ca<sup>2+</sup> and ADP: Focusing on the auto-oscillation (SPOC)」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル