Stepwise enzymatic dephosphorylation of inositol 1,4,5-trisphosphate to inositol in liver

Diane J. Storey*, Stephen B. Shears, Christopher J. Kirk, Robert H. Michell

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

170 Citations (Scopus)


Many receptors for hormones, neurotransmitters and other signals cause hydrolysis of phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2) and effect a rise in cytosolic Ca2+ concentration1-7. The inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) liberated during PtdIns(4,5)P2 breakdown seems to serve as a second messenger that activates the release of Ca2+ from a nonmitochondrial intracellular compartment7-12. As expected if it is an important intracellular messenger, Ins(1,4,5)P3 is relatively rapidly degraded, both within stimulated cells13,14 and when added to homogenates of blowfly salivary gland15 or to permeabilized, but not intact, hepatocytes10. Here we report that the dephosphorylation reactions responsible for the conversion of Ins(1,4,5)P3 to free inositol in rat liver are catalysed by two or more enzymes, and that these reactions are distributed between the plasma membrane and cytosol. The Ins(1,4,5)P3 5-phosphatase and inositol 1-phosphate (Ins(1)P) phosphatase of liver appear similar to enzymes described previously in erythrocytes16 and brain17.

Original languageEnglish
Pages (from-to)374-376
Number of pages3
Issue number5992
Publication statusPublished - 1 Dec 1984

ASJC Scopus subject areas

  • Medicine(all)
  • General


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