The effect of caffeine, adenosine, and buffer ionic composition on the induction of cell‐surface cAMP binding during starvation of Dictyostelium discoideum

Iain A.S. Drummond, Rex L. Chisholm*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

We have analyzed the effects of the cAMP relay inhibitor, caffeine, and the receptor antagonist, adenosine, on the regulation of the cell‐surface cAMP receptor in suspensionstarved Dictyostelium discoideum cells by measuring ammonium sulfate‐stabilized binding of [3‐H]cAMP to intact cells. When cells were starved in fast (230 r.p.m.) shaken suspension in 10 mM Na+/5 mM K+ phosphate buffer, pH 6.5, plus 1 mM CaCl2 and 2.5 mM MgCl2, and assayed for specific cAMP binding, receptor accumulation peaked at approximately 6 hours, reaching a maximum of 1.5 pmol cAMP bound/107 cells (saturation binding). Neither caffeine nor adenosine inhibited the accumulation of cAMP receptors. Similar results were obtained in caffeine‐treated, slow shaken (90 r.p.m.) suspension cultures. These results suggest that starvation alone is sufficient stimulus to induce the cAMP receptor. We have also tested the effects of different buffer ionic compositions on the accumulation of cAMP receptors. Elevation of the monovalent ion concentration to 30‐40 mM was found to significantly inhibit the induction of cAMP receptors.

Original languageEnglish (US)
Pages (from-to)293-301
Number of pages9
JournalDevelopmental Genetics
Volume9
Issue number4-5
DOIs
StatePublished - 1988

Keywords

  • developmental regulation
  • developmental signals
  • ions
  • receptor regulation

ASJC Scopus subject areas

  • Genetics
  • Developmental Biology
  • Cell Biology

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