Antagonistic forces generated by myosin II and cytoplasmic dynein regulate microtubule turnover, movement, and organization in interphase cells

doi:10.1073/pnas.141224198

Antagonistic forces generated by myosin II and cytoplasmic dynein regulate microtubule turnover, movement, and organization in interphase cells

^*Program in Molecular and Cellular Biology, and Departments of ^†Biology, and ^‡Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003

Communicated by Shinya Inoué, Marine Biological Laboratory, Woods Hole, MA (received for review November 1, 2000)

Abstract

Photoactivation of caged fluorescent tubulin was used mark the microtubule (MT) lattice and monitor MT behavior in interphase cells. A broadening of the photoactivated region occurred as MTs moved bidirectionally. MT movement was not inhibited when MT assembly was suppressed with nocodazole or Taxol; MT movement was suppressed by inhibition of myosin light chain kinase with ML7 or by a peptide inhibitor. Conversely, MT movement was increased after inhibition of cytoplasmic dynein with the antibody 70.1. In addition, the half-time for MT turnover was decreased in cells treated with ML7. These results demonstrate that myosin II and cytoplasmic dynein contribute to a balance of forces that regulates MT organization, movement, and turnover in interphase cells.

microtubule motion

Footnotes

↵ § To whom reprint requests should be sent at present address: Morrill Science Center, University of Massachusetts, Amherst, MA 01003. E-mail: patw{at}bio.umass.edu.
↵ ¶ Kapoor, T. M., Mayer, T. U., Desai, A., Maddox, P., Salmon, E. D., Schreiber, S. L. & Mitchison, T. J. (1999) Mol. Biol. Cell 10, 128 (abstr).
Abbreviations:

BDM,

2,3 butanedione monoxime;

MLCK,

myosin light chain kinase;

MT,

microtubule