Inter-sarcomere coordination in muscle revealed through individual sarcomere response to quick stretch

Yuta Shimamoto, Madoka Suzuki, Sergey Mikhailenko, Kenji Yasuda, Shin'ichi Ishiwata

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

The force generation and motion of muscle are produced by the collective work of thousands of sarcomeres, the basic structural units of striated muscle. Based on their series connection to form a myofibril, it is expected that sarcomeres are mechanically and/or structurally coupled to each other. However, the behavior of individual sarcomeres and the coupling dynamics between sarcomeres remain elusive, because muscle mechanics has so far been investigated mainly by analyzing the averaged behavior of thousands of sarcomeres in muscle fibers. In this study, we directly measured the length-responses of individual sarcomeres to quick stretch at partial activation, using micromanipulation of skeletal myofibrils under a phase-contrast microscope. The experiments were performed at ADP-activation (1 mM MgATP and 2 mM MgADP in the absence of Ca 2+) and also at Ca2+-activation (1 mM MgATP at pCa 6.3) conditions. We show that under these activation conditions, sarcomeres exhibit 2 distinct types of responses, either "resisting" or "yielding," which are clearly distinguished by the lengthening distance of single sarcomeres in response to stretch. These 2 types of sarcomeres tended to coexist within the myofibril, and the sarcomere "yielding" occurred in clusters composed of several adjacent sarcomeres. The labeling of Z-line with anti-α-actinin antibody significantly suppressed the clustered sarcomere "yielding." These results strongly suggest that the contractile system of muscle possesses the mechanism of structure-based inter-sarcomere coordination.

Original languageEnglish
Pages (from-to)11954-11959
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number29
DOIs
Publication statusPublished - 2009 Jul 21

Fingerprint

Sarcomeres
Muscles
Myofibrils
Adenosine Diphosphate
Adenosine Triphosphate
Micromanipulation
Actinin
Striated Muscle
Mechanics
Anti-Idiotypic Antibodies

Keywords

  • Myofibril
  • Partial activation
  • Sarcomere "yielding"
  • Z-line

ASJC Scopus subject areas

  • General

Cite this

Inter-sarcomere coordination in muscle revealed through individual sarcomere response to quick stretch. / Shimamoto, Yuta; Suzuki, Madoka; Mikhailenko, Sergey; Yasuda, Kenji; Ishiwata, Shin'ichi.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 106, No. 29, 21.07.2009, p. 11954-11959.

Research output: Contribution to journalArticle

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