Characterization of ring-like F-actin structure as a mechanical partner for spindle positioning in mitosis

PLoS One. 2014 Oct 9;9(10):e102547. doi: 10.1371/journal.pone.0102547. eCollection 2014.

Abstract

Proper spindle positioning and orientation are essential for accurate mitosis which requires dynamic interactions between microtubule and actin filament (F-actin). Although mounting evidence demonstrates the role of F-actin in cortical cytoskeleton dynamics, it remains elusive as to the structure and function of F-actin-based networks in spindle geometry. Here we showed a ring-like F-actin structure surrounding the mitotic spindle which forms since metaphase and maintains in MG132-arrested metaphase HeLa cells. This cytoplasmic F-actin structure is relatively isotropic and less dynamic. Our computational modeling of spindle position process suggests a possible mechanism by which the ring-like F-actin structure can regulate astral microtubule dynamics and thus mitotic spindle orientation. We further demonstrated that inhibiting Plk1, Mps1 or Myosin, and disruption of microtubules or F-actin polymerization perturbs the formation of the ring-like F-actin structure and alters spindle position and symmetric division. These findings reveal a previously unrecognized but important link between mitotic spindle and ring-like F-actin network in accurate mitosis and enables the development of a method to theoretically illustrate the relationship between mitotic spindle and cytoplasmic F-actin.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actin Cytoskeleton / metabolism
  • Actins / metabolism*
  • Cell Line, Tumor
  • Cytoskeleton / metabolism
  • Cytoskeleton / physiology
  • HeLa Cells
  • Humans
  • Metaphase / physiology
  • Microtubules / metabolism
  • Mitosis / physiology*
  • Myosins / metabolism
  • Spindle Apparatus / metabolism*
  • Spindle Apparatus / physiology*

Substances

  • Actins
  • Myosins