Calcium mobilization stimulates Dictyostelium discoideum shear-flow-induced cell motility

Sébastien Fache, Jérémie Dalous, Mads Engelund, Christian Hansen, François Chamaraux, Bertrand Fourcade, Michel Satre, Peter Devreotes, Franz Bruckert

Research output: Contribution to journalArticle

Abstract

Application of hydrodynamic mild shear stress to adherent Dictyostelium discoideum vegetative cells triggers active actin cytoskeleton remodeling resulting in net cell movement along the flow. The average cell speed is strongly stimulated by external calcium (Ca2+, K50%=22 μM), but the directionality of the movement is almost unaffected. This calcium concentration is ten times higher than the one promoting cell adhesion to glass surfaces (K50%=2 μM). Addition of the calcium chelator EGTA or the Ca2+-channel blocker gadolinium (Gd3+) transiently stops cell movement. Monitoring the evolution of cell-surface contact area with time reveals that calcium stimulates cell speed by increasing the amplitude of both protrusion and retraction events at the cell edge, but not the frequency. As a consequence, with saturating external calcium concentrations, cells are sensitive to very low shear forces (20 pN; σ=0.1 Pa). Moreover, a null-mutant lacking the unique Gβ subunit does not respond to external Ca2+ changes (K50:%>1000 μM), although the directionality of the movement is comparable with that of wild-type cells. Furthermore, cells lacking the inositoi 1,4,5-trisphosphate receptor (IP3-receptor) exhibit a markedly reduced Ca2+ sensitivity. Thus, calcium release from internal stores and calcium entry through the plasma membrane modulate cell speed in response to shear stress.

Original languageEnglish (US)
Pages (from-to)3445-3457
Number of pages13
JournalJournal of cell science
Volume118
Issue number15
DOIs
StatePublished - Aug 1 2005

Keywords

  • Calcium
  • Dictyostelium discoideum
  • Heterotrimeric G proteins
  • Hydrodynamic flow
  • Mechanosensitivity
  • Motility

ASJC Scopus subject areas

  • Cell Biology

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    Fache, S., Dalous, J., Engelund, M., Hansen, C., Chamaraux, F., Fourcade, B., Satre, M., Devreotes, P., & Bruckert, F. (2005). Calcium mobilization stimulates Dictyostelium discoideum shear-flow-induced cell motility. Journal of cell science, 118(15), 3445-3457. https://doi.org/10.1242/jcs.02461