A soluble motor from the alga Nitella supports fast movement of actin filaments in vitro

Marcelo N. Rivolta, Raul Urrutia, Bechara Kachar

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

In the streaming cytoplasm of the Characean algae cell, the movement of organelles along actin bundles occurs at a striking rate of up to 60 μm s-1. To further characterize the molecular mechanisms responsible for this phenomenon, we have reconstituted the movement of actin filaments in vitro using defined biochemical components. We report that only a soluble cytoplasmic fraction devoid of organelles and filamentous material supports the movement of fluorescent-labeled actin filaments on glass at a rate of up to 60 μm s-1. This fraction also contains the K+-EDTA ATPase and the actin-activated Mg2+ ATPase activities characteristic of myosin proteins. Therefore, on the basis of these observations, we conclude that Nitella cells have a soluble pool of non-filamentous myosin molecules with the mechanochemical properties expected for a motor responsible for cytoplasmic streaming in vivo. The preparation and conditions described here should be useful for the purification of this translocator.

Original languageEnglish (US)
Pages (from-to)1-4
Number of pages4
JournalBBA - Bioenergetics
Volume1232
Issue number1-2
DOIs
StatePublished - Nov 21 1995

Keywords

  • Actin
  • Motility
  • Myosin
  • Video microscopy

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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