Journal of Lipid Research (Mar 2007)

Use of the GRP1 PH domain as a tool to measure the relative levels of PtdIns(3,4,5)P3 through a protein-lipid overlay approach

  • Hervé Guillou,
  • Charlotte Lécureuil,
  • Karen E. Anderson,
  • Sabine Suire,
  • G. John Ferguson,
  • Chris D. Ellson,
  • Alexander Gray,
  • Nullin Divecha,
  • Phillip T. Hawkins,
  • Len R. Stephens

Journal volume & issue
Vol. 48, no. 3
pp. 726 – 732

Abstract

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We describe a novel approach to the relative quantification of phosphatidylinositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] and its application to measure, in neutrophils, the activation of phosphoinositide 3-kinase (PI3K). This protein-lipid overlay-based assay allowed us to confirm and extend the observations, first, that N-formyl-methionyl-leucyl-phenylalanine (fMLP) stimulation of primed human neutrophils leads to a transient and biphasic increase in PtdIns(3,4,5)P3 levels and, second, that the ability of fMLP to stimulate PtdIns(3,4,5)P3 accumulation in neutrophils isolated from mice carrying a Ras-insensitive (‘DASAA‘) knock-in of PI3Kγ (p110γDASAA/DASAA) is substantially dependent on the Ras binding domain of PI3Kγ.

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