The pathway of myo-inositol 1,3,4-trisphosphate dephosphorylation in liver.

S. B. Shears, C. J. Kirk, R. H. Michell

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

We studied the dephosphorylation pathway for Ins(1,3,4)P3 (inositol 1,3,4-trisphosphate) by liver homogenates and soluble and particulate subfractions incubated in media resembling physiological ionic strength and pH. Ins(1,3,4)P3 was dephosphorylated to two InsP2 (inositol bisphosphate) isomers, one of which is Ins(3,4)P2 [Shears, Parry, Tang, Irvine, Michell & Kirk (1987) Biochem. J. 246, 139-147]. The second InsP2 is the 1,3 isomer. Ins(3,4)P2 is dephosphorylated to inositol 3-phosphate by an enzyme activity located in both soluble and particulate fractions. The phosphatase(s) that attacks Ins(1,3)P2 was largely soluble, but we have not determined which phosphate(s) is removed. When the initial substrate concentration was 1 nM, the rate of dephosphorylation of Ins(1,4)P2 greater than Ins(1,3)P2 greater than Ins(3,4)P2. None of these bisphosphates was phosphorylated when incubated with liver homogenates and 5 mM-ATP, but their rates of dephosphorylation were then decreased.

Original languageEnglish
Pages (from-to)977-980
Number of pages4
JournalThe Biochemical journal
Volume248
Issue number3
DOIs
Publication statusPublished - 1 Jan 1987

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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