eLife (Feb 2018)

Bipolar filaments of human nonmuscle myosin 2-A and 2-B have distinct motile and mechanical properties

  • Luca Melli,
  • Neil Billington,
  • Sara A Sun,
  • Jonathan E Bird,
  • Attila Nagy,
  • Thomas B Friedman,
  • Yasuharu Takagi,
  • James R Sellers

DOI
https://doi.org/10.7554/eLife.32871
Journal volume & issue
Vol. 7

Abstract

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Nonmusclemyosin 2 (NM-2) powers cell motility and tissue morphogenesis by assembling into bipolar filaments that interact with actin. Although the enzymatic properties of purified NM-2 motor fragments have been determined, the emergent properties of filament ensembles are unknown. Using single myosin filament in vitro motility assays, we report fundamental differences in filaments formed of different NM-2 motors. Filaments consisting of NM2-B moved processively along actin, while under identical conditions, NM2-A filaments did not. By more closely mimicking the physiological milieu, either by increasing solution viscosity or by co-polymerization with NM2-B, NM2-A containing filaments moved processively. Our data demonstrate that both the kinetic and mechanical properties of these two myosins, in addition to the stochiometry of NM-2 subunits, can tune filament mechanical output. We propose altering NM-2 filament composition is a general cellular strategy for tailoring force production of filaments to specific functions, such as maintaining tension or remodeling actin.

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