Cytosolic inositol 1,4,5-trisphosphate dynamics during intracellular calcium oscillations in living cells

Toru Matsu-ura, Takayuki Michikawa*, Takafumi Inoue, Atsushi Miyawaki, Manabu Yoshida, Katsuhiko Mikoshiba

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

97 Citations (Scopus)


We developed genetically encoded fluorescent inositol 1,4,5-trisphosphate (IP3) sensors that do not severely interfere with intracellular Ca2+ dynamics and used them to monitor the spatiotemporal dynamics of both cytosolic IP3 and Ca2+ in single HeLa cells after stimulation of exogenously expressed metabotropic glutamate receptor 5a or endogenous histamine receptors. IP3 started to increase at a relatively constant rate before the pacemaker Ca2+ rise, and the subsequent abrupt Ca2+ rise was not accompanied by any acceleration in the rate of increase in IP3. Cytosolic [IP3] did not return to its basal level during the intervals between Ca2+ spikes, and IP3 gradually accumulated in the cytosol with a little or no fluctuations during cytosolic Ca2+ oscillations. These results indicate that the Ca2+-induced regenerative IP3 production is not a driving force of the upstroke of Ca2+ spikes and that the apparent IP3 sensitivity for Ca2+ spike generation progressively decreases during Ca2+ oscillations.

Original languageEnglish
Pages (from-to)755-765
Number of pages11
JournalJournal of Cell Biology
Issue number5
Publication statusPublished - 2006 Jun 5
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology


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