Functional coupling of phosphatidylinositol 4,5-bisphosphate to inositol 1,4,5-trisphosphate receptor

Vitalie D. Lupu, Elena Kaznacheyeva, U. Murali Krishna, J R Falck, Ilya Bezprozvanny

Research output: Contribution to journalArticle

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Abstract

The inositol 1,4,5-trisphosphate receptor (InsP3R) plays a key role in intracellular Ca2+ signaling. InsP3R is activated by InsP3 produced from phosphatidylinositol 4,5-bisphosphate (PIP2) by phospholipase C cleavage. Using planar lipid bilayer reconstitution technique, we demonstrate here that rat cerebellar InsP3R forms a stable inhibitory complex with endogenous PIP2. Disruption of InsP3R-PIP2 interaction by specific anti-PIP2 monoclonal antibody resulted in 3-4-fold increase in InsP3R activity and 10- fold shift in apparent affinity for InsP3. Exogenously added PIPe blocks InsP3 binding to InsP3R and inhibits InsP3R activity. Similar results were obtained with a newly synthesized water soluble analog of PIP2, dioctanoyl- (4,5)PIP2, indicating that insertion of PIP2 into membrane is not required to exert its inhibitory effects on the InsP3R. We hypothesize that the functional link between InsP3R and PIP2 described in the present report provides a basis for a local, rapid, and efficient coupling between phospholipase C activation, PIP2 hydrolysis, and intracellular Ca2+ wave initiation in neuronal and non-neuronal cells.

Original languageEnglish (US)
Pages (from-to)14067-14070
Number of pages4
JournalJournal of Biological Chemistry
Volume273
Issue number23
DOIs
StatePublished - Jun 5 1998

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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