Blebbing of Dictyostelium cells in response to chemoattractant

Paul D. Langridge, Robert R. Kay

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

Stimulation of Dictyostelium cells with a high uniform concentration of the chemoattractant cyclic-AMP induces a series of morphological changes, including cell rounding and subsequent extension of pseudopodia in random directions. Here we report that cyclic-AMP also elicits blebs and analyse their mechanism of formation. The surface area and volume of cells remain constant during blebbing indicating that blebs form by the redistribution of cytoplasm and plasma membrane rather than the exocytosis of internal membrane coupled to a swelling of the cell. Blebbing occurs immediately after a rapid rise and fall in submembraneous F-actin, but the blebs themselves contain little F-actin as they expand. A mutant with a partially inactivated Arp2/3 complex has a greatly reduced rise in F-actin content, yet shows a large increase in blebbing. This suggests that bleb formation is not enhanced by the preceding actin dynamics, but is actually inhibited by them. In contrast, cells that lack myosin-II completely fail to bleb. We conclude that bleb expansion is likely to be driven by hydrostatic pressure produced by cortical contraction involving myosin-II. As blebs are induced by chemoattractant, we speculate that hydrostatic pressure is one of the forces driving pseudopod extension during movement up a gradient of cyclic-AMP. Crown

Original languageEnglish (US)
Pages (from-to)2009-2017
Number of pages9
JournalExperimental Cell Research
Volume312
Issue number11
DOIs
StatePublished - Jul 1 2006
Externally publishedYes

Keywords

  • Arp2/3 complex
  • Blebbing
  • Cell motility
  • Chemoattractant
  • Dictyostelium
  • Hydrostatic pressure
  • Myosin-II

ASJC Scopus subject areas

  • Cell Biology

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