Serum-induced membrane depolarization in quiescent fibroblasts: Activation of a chloride conductance through the G protein-coupled LPA receptor

Friso R. Postma, Kees Jalink, Trudi Hengeveld, A. G M Bot, Jacqueline Alblas, Hugo R. De Jonge, Wouter H. Moolenaar*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

45 Citations (Scopus)

Abstract

Serum stimulation of quiescent fibroblasts leads to a dramatic depolarization of the plasma membrane; however, the identity of the active serum factor(s) and the underlying mechanism are unknown. We find that this serum activity is attributable to albumin-bound lysophosphatidic acid (LPA) acting on its own G protein-coupled receptor, and that membrane depolarization is due to activation of an anion conductance mediating Cl- efflux. This depolarizing Cl- current can also be activated by thrombin and neuropeptide receptors; it is distinct from volume-regulated Cl- currents. Activation of the Cl- current consistently follows stimulation of phospholipase C and coincides with remodelling of the actin cytoskeleton, which is regulated by the Ras-related GTPase Rho. However, the response is not due to Ca2+/protein kinase C signalling and requires neither Rho nor Ras activation. The results indicate that in quiescent fibroblasts, LPA and other G protein-coupled receptor agonists evoke membrane depolarization by activating a new type of Cl- channel through a signalling pathway that is closely associated with phosphoinositide hydrolysis, yet independent of known second messengers.

Original languageEnglish
Pages (from-to)63-72
Number of pages10
JournalEMBO Journal
Volume15
Issue number1
Publication statusPublished - 2 Jan 1996

Keywords

  • Chloride current
  • Fibroblasts
  • G protein-coupled receptor
  • Lysophosphatidic acid
  • Membrane depolarization

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