A novel actin binding site of myosin required for effective muscle contraction

Boglárka H. Várkuti, Zhenhui Yang, Bálint Kintses, Péter Erdélyi, Irén Bárdos-Nagy, Attila L. Kovács, Péter Hári, Miklás Kellermayer, Tibor Vellai, András Málnási-Csizmadia

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37 Citations (Scopus)


F-actin serves as a track for myosin's motor functions and activates its ATPase activity by several orders of magnitude, enabling actomyosin to produce effective force against load. Although actin activation is a ubiquitous property of all myosin isoforms, the molecular mechanism and physiological role of this activation are unclear. Here we describe a conserved actin-binding region of myosin named the 'activation loop', which interacts with the N-terminal segment of actin. We demonstrate by biochemical, biophysical and in vivo approaches using transgenic Caenorhabditis elegans strains that the interaction between the activation loop and actin accelerates the movement of the relay, stimulating myosin's ATPase activity. This interaction results in efficient force generation, but it is not essential for the unloaded motility. We conclude that the binding of actin to myosin's activation loop specifically increases the ratio of mechanically productive to futile myosin heads, leading to efficient muscle contraction.

Original languageEnglish
Pages (from-to)299-306
Number of pages8
JournalNature Structural and Molecular Biology
Issue number3
Publication statusPublished - Mar 1 2012


ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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