ZFIN ID: ZDB-PUB-200422-1
Spindle-F-actin interactions in mitotic spindles in an intact vertebrate epithelium
Kita, A.M., Swider, Z.T., Erofeev, I., Halloran, M.C., Goryachev, A.B., Bement, W.M.
Date: 2019
Source: Molecular biology of the cell   30: 1645-1654 (Journal)
Registered Authors: Halloran, Mary
Keywords: none
MeSH Terms:
  • Actins/metabolism*
  • Animals
  • Cell Survival
  • Endoplasmic Reticulum/metabolism
  • Epithelial Cells/metabolism
  • Epithelium/metabolism*
  • Formins/metabolism
  • Spindle Apparatus/metabolism*
  • Spindle Poles/metabolism
  • Xenopus laevis/metabolism*
PubMed: 31091161 Full text @ Mol. Biol. Cell
Mitotic spindles are well known to be assembled from and dependent on microtubules. In contrast, whether actin filaments (F-actin) are required for or are even present in mitotic spindles has long been controversial. Here we have developed improved methods for simultaneously preserving F-actin and microtubules in fixed samples and exploited them to demonstrate that F-actin is indeed associated with mitotic spindles in intact Xenopus laevis embryonic epithelia. We also find that there is an "F-actin cycle," in which the distribution and organization of spindle F-actin changes over the course of the cell cycle. Live imaging using a probe for F-actin reveals that at least two pools of F-actin are associated with mitotic spindles: a relatively stable internal network of cables that moves in concert with and appears to be linked to spindles, and F-actin "fingers" that rapidly extend from the cell cortex toward the spindle and make transient contact with the spindle poles. We conclude that there is a robust endoplasmic F-actin network in normal vertebrate epithelial cells and that this network is also a component of mitotic spindles. More broadly, we conclude that there is far more internal F-actin in epithelial cells than is commonly believed.