Novel function of phosphatidylinositol 4,5-bisphosphate as a cofactor for brain membrane phospholipase D

Authors

Modechai Liscovitch
Vered Chalifa
Paolo Pertile
Ching-Shih Chen, University of Rhode Island
Lewis C. Cantley

Document Type

Article

Date of Original Version

1994

Department

Pharmacognosy and Environmental Health

Abstract

The activation of phospholipase D (PLD) is a receptor-mediated event that has been implicated in signal transduction and membrane traffic in eukaryotic cells. Little is known about the biochemical and molecular properties of signal-activated PLDs, and none has been isolated. Here we report that phosphatidylinositol 4,5-bisphosphate (PIP₂) potently stimulates brain membrane PLD activity in vitro in a highly specific manner. PIP2 increases 10-fold the maximal activity of a partially purified PLD with an EC50 of < 0.5 mol %. Other acidic phospholipids, including phosphatidylinositol 4-phosphate, phosphatidylinositol, phosphatidylserine, and phosphatidic acid, are completely or nearly ineffective. Neomycin, a high affinity ligand of PIP₂, inhibits membrane-bound PLD but has no effect on the activity of a detergent-solubilized or partially purified enzyme. The addition of PIP₂ restores the sensitivity of partially purified PLD to neomycin inhibition, indicating that neomycin blocks membrane PLD activity by binding to endogenous PIP₂. These results define a novel function of PIP₂ as a cofactor for brain membrane PLD and suggest that PIP2 synthesis and hydrolysis could be important determinants in regulating PLD action in signal transduction and membrane transport.

Citation/Publisher Attribution

Liscovitch, M., Chalifa, V., Pertile, P., Chen, C.-S., & Cantley, L. C. (1994). Novel function of phosphatidylinositol 4,5-bisphosphate as a cofactor for brain membrane phospholipase D. Journal of Biological Chemistry, 269(34), 21403-21406. Retrieved from http://www.jbc.org/content/269/34/21403.

Available at: http://www.jbc.org/content/269/34/21403