G-protein activation, intracellular ca2+ mobilization and phosphorylation studies of membrane currents induced by A1F4- in xenopus oocytes

Cheil Moon, Scott P. Fraser, Mustafa B A Djamgoz

Research output: Contribution to journalArticle

Abstract

We have examined the electrophysiological responses induced by aluminium fluoride (AlF4-) and carbachol in Xenopus oocytes. Application of AlF4- induced Ca2+-dependent oscillatory and smooth C1- currents. Pre-treatment of oocytes with microinjected guanosine 5'-0 (2-thiodiphosphate) diminished the currents, indicating that the effect of AlF4- occurred through G-protein activation. Confocal imaging of intracellular Ca2+ clearly demonstrated that AlF4- could increase the internal Ca2+ concentration in oocytes in the absence of external Ca2+. A protein kinase (PK) activator (4-β-phorbol 12,13-dibutyrate) decreased the AlF4- induced membrane currents, whereas a PK inhibitor (staurosporine) caused an increase. On the other hand, the protein phosphatase inhibitor (okadaic acid) showed little effect. Although the effects of the phosphorylating/dephosphorylating agents on the carbachol-induced currents were qualitatively similar to the case of AlF4-, some quantitative difference was noted. The results are discussed in terms of the signaling pathways involving muscarinic receptors and G-protein(s) in Xenopus oocytes.

Original languageEnglish (US)
Pages (from-to)497-504
Number of pages8
JournalCellular Signalling
Volume9
Issue number7
DOIs
Publication statusPublished - Nov 1997
Externally publishedYes

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Keywords

  • Acetylcholine
  • Aluminium fluoride
  • Calcium
  • G-protein
  • Phosphatidyl inositol
  • Phosphorylation
  • Xenopus oocyte

ASJC Scopus subject areas

  • Cell Biology

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