Phosphatidylinositol 3,5-bisphosphate Defines a Novel PI 3-kinase Pathway in Resting Mouse Fibroblasts

Biochem J. 1997 May 1;323 ( Pt 3)(Pt 3):597-601. doi: 10.1042/bj3230597.


PtdIns(3,5)P2 is identified as the product of an agonist-independent, wortmannin-sensitive pathway in resting mouse cells. Results are presented here to indicate that PtdIns(3,5)P2 is formed by phosphorylation of PtdIns3P at the D-5 position, and they suggest that relatively constant cellular levels of PtdIns3P and PtdIns(3, 5)P2 are maintained by the concerted action of PtdIns3P 5-kinase and PtdIns(3,5)P2 5-phosphatase. These studies imply a novel mechanism for the action of PtdIns-specific phosphoinositide 3-hydroxykinases in mammalian cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Androstadienes / pharmacology
  • Animals
  • Cell Line
  • Enzyme Inhibitors / pharmacology
  • Fibroblasts / drug effects
  • Fibroblasts / enzymology*
  • Interphase
  • Mice
  • Phosphatidylinositol 3-Kinases
  • Phosphatidylinositol Phosphates / metabolism*
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Wortmannin


  • Androstadienes
  • Enzyme Inhibitors
  • Phosphatidylinositol Phosphates
  • phosphatidylinositol 3,5-diphosphate
  • phosphatidylinositol 3-phosphate
  • Phosphatidylinositol 3-Kinases
  • Phosphotransferases (Alcohol Group Acceptor)
  • Wortmannin