Myosin II governs intracellular pressure and traction by distinct tropomyosin-dependent mechanisms

Mol Biol Cell. 2019 May 1;30(10):1170-1181. doi: 10.1091/mbc.E18-06-0355. Epub 2019 Mar 13.

Abstract

Two-dimensional (2D) substrate rigidity promotes myosin II activity to increase traction force in a process negatively regulated by tropomyosin (Tpm) 2.1. We recently discovered that actomyosin contractility can increase intracellular pressure and switch tumor cells from low-pressure lamellipodia to high-pressure lobopodial protrusions during three-dimensional (3D) migration. However, it remains unclear whether these myosin II-generated cellular forces are produced simultaneously, and by the same molecular machinery. Here we identify Tpm 1.6 as a positive regulator of intracellular pressure and confirm that Tpm 2.1 is a negative regulator of traction force. We find that Tpm 1.6 and 2.1 can control intracellular pressure and traction independently, suggesting these myosin II-dependent forces are generated by distinct mechanisms. Further, these tropomyosin-regulated mechanisms can be integrated to control complex cell behaviors on 2D and in 3D environments.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actin Cytoskeleton / physiology
  • Actomyosin / physiology
  • Cell Movement
  • Cytoskeletal Proteins
  • Extracellular Matrix
  • Fibroblasts / metabolism
  • Foreskin / metabolism
  • Humans
  • Male
  • Myosin Type II / metabolism
  • Myosin Type II / physiology*
  • Pressure
  • Primary Cell Culture
  • Pseudopodia / physiology
  • Traction
  • Tropomyosin / metabolism
  • Tropomyosin / physiology*

Substances

  • Cytoskeletal Proteins
  • TPM1 protein, human
  • TPM2 protein, human
  • Tropomyosin
  • Actomyosin
  • Myosin Type II