Structural and functional reconstitution of thin filaments in the contractile apparatus of cardiac muscle

Hideaki Fujita, Kenji Yasuda, Shigehiko Niitsu, Takashi Funatsu, Shin'ichi Ishiwata*

*この研究の対応する著者

研究成果: Article査読

49 被引用数 (Scopus)

抄録

The muscle contractile apparatus has a highly ordered liquid crystalline structure. The molecular mechanism underlying the formation of this apparatus remains, however, to be elucidated. Selective removal and reconstitution of the components are useful means of examining this mechanism. In addition, this approach is a powerful technique for examining the structure and function of a specific component of the contractile system. In this study we have achieved the structural and functional reconstitution of thin filaments in the cardiac contractile apparatus. First, all thin filaments other than short fragments at the Z line were removed by treatment with gelsolin. Under these conditions no active tension could be generated. By incorporating exogenous actin into these thin filament-free fibers, actin filaments were reconstituted, and active tension, which was insensitive to Ca2+, was restored. The active tension after the reconstitution of thin filaments reached 135 ± 64% of the original level. The augmentation of tension was attributable to the elongation of reconstituted filaments. As another possibility for augmented tension generation, we suggest the presence of an inhibitory system that was not reconstituted. In any case, the thin filaments of the cardiac contractile apparatus are considered to be assembled so as not to develop the highest degree of tension. Incorporation of the tropomyosin- troponin complex fully restored Ca2+ sensitivity without affecting maximum tension. The present results indicate that a muscle contractile apparatus with a higher order structure and function can be constructed by the self- assembly of constituent proteins.

本文言語English
ページ(範囲)2307-2318
ページ数12
ジャーナルBiophysical Journal
71
5
DOI
出版ステータスPublished - 1996 11
外部発表はい

ASJC Scopus subject areas

  • 生物理学

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