Phalloidin affects the myosin-dependent sliding velocities of actin filaments in a bound-divalent cation dependent manner

Kiyotaka Tokuraku, Taro Q.P. Uyeda

研究成果: Article査読

8 被引用数 (Scopus)

抄録

We examined sliding velocities in vitro of four types of actin filaments, that is, filaments with Ca 2+ or Mg 2+ bound at the high affinity metal binding site, each with rhodamine phalloidin bound with a high or low stoichiometry. When surfaces coated with a high density of heavy meromyosin (HMM) were used, high stoichiometric concentrations of rhodamine phalloidin reduced sliding velocities of only Ca 2+-actin filaments, by 40%. As the HMM density on surfaces was reduced, continuous movement of actin filaments became dependent on the presence of methylcellulose and sliding velocities of all four types became progressively slower. Interestingly, Ca 2+-actin filaments with a high stoichiometric concentration of rhodamine phalloidin were the fastest among the four types of filaments on sparse HMM surfaces. In contrast, phalloidin did not affect steady state ATPase activities of HMM in the presence of Ca 2+- or Mg 2+-actin filaments. We speculate that the reversal of the order of sliding velocities among the four types of actin filaments between high and low densities of HMM relates with different axial elasticity of the actin filaments, so that stiffer filaments move slower on dense HMM surfaces, but faster on sparse surfaces, than elastic ones.

本文言語English
ページ(範囲)371-378
ページ数8
ジャーナルJournal of Muscle Research and Cell Motility
22
4
DOI
出版ステータスPublished - 2001
外部発表はい

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Cell Biology

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