Keratocytes pull with similar forces on their dorsal and ventral surfaces

Catherine G. Galbraith, Michael P. Sheetz

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


As cells move forward, they pull rearward against extracellular matrices (ECMs), exerting traction forces. However, no rearward forces have been seen in the fish keratocyte. To address this discrepancy, we have measured the propulsive forces generated by the keratocyte lamella on both the ventral and the dorsal surfaces. On the ventral surface, a micromachined device revealed that traction forces were small and rearward directed under the lamella, changed direction in front of the nucleus, and became larger under the cell body. On the dorsal surface of the lamella, an optical gradient trap measured rearward forces generated against fibronectin-coated beads. The retrograde force exerted by the cell on the bead increased in the thickened region of the lamella where myosin condensation has been observed (Svitkina, T.M., A.B. Verkhovsky, K.M. McQuade, and G.G. Borisy. 1997. J. Cell Biol. 139: 397-415). Similar forces were generated on both the ventral (0.2 nN/μm2) and the dorsal (0.4 nN/μm2) surfaces of the lamella, suggesting that dorsal matrix contacts are as effectively linked to the force-generating cytoskeleton as ventral contacts. The correlation between the level of traction force and the density of myosin suggests a model for keratocyte movement in which myosin condensation in the perinuclear region generates rearward forces in the lamella and forward forces in the cell rear.

Original languageEnglish (US)
Pages (from-to)1313-1323
Number of pages11
JournalJournal of Cell Biology
Issue number6
StatePublished - Dec 13 1999
Externally publishedYes


  • Cytoskeleton
  • Laser trap
  • Micromachine
  • Migration
  • Traction force

ASJC Scopus subject areas

  • Cell Biology


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