An essential role for the SHIP2-dependent negative feedback loop in neuritogenesis of nerve growth factor-stimulated PC12 cells

J Cell Biol. 2007 Jun 4;177(5):817-27. doi: 10.1083/jcb.200609017. Epub 2007 May 29.

Abstract

The local accumulation of phosphatidylinositol (3,4,5) trisphosphate (PIP(3)) and resulting activation of Rac1/Cdc42 play a critical role in nerve growth factor (NGF)-induced neurite outgrowth. To further explore the mechanism, we visualized PIP(3), phosphatidylinositol (3,4) bisphosphate, and Rac1/Cdc42 activities by fluorescence resonance energy transfer (FRET) imaging in NGF-stimulated PC12 cells. Based on the obtained FRET images, and with the help of in silico kinetic reaction model, we predicted that PI-5-phosphatase negatively regulates PIP(3) upon NGF stimulation. In agreement with this model, depletion of Src homology 2 domain-containing inositol polyphosphate 5-phosphatase 2 (SHIP2) markedly potentiated NGF-induced Rac1/Cdc42 activation and PIP(3) accumulation and considerably increased the number and the length of neurites in phosphate and tensin homologue-depleted PC12 cells. Further refinement of the computational model predicted Rac1 regulation of PI3-kinase and SHIP2, which was also validated experimentally. We propose that the SHIP2-mediated negative feedback on PIP(3) coordinately works with the PI3-kinase-mediated positive feedback to form an initial protrusive pattern and, later, to punctuate the PIP(3) accumulation to maintain proper neurite outgrowth.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Computer Simulation
  • Feedback, Physiological
  • Fluorescence Resonance Energy Transfer
  • Inositol Polyphosphate 5-Phosphatases
  • Kinetics
  • Nerve Growth Factor / pharmacology*
  • Nerve Net / growth & development
  • Neurites / drug effects
  • Neurites / enzymology*
  • Neurites / ultrastructure
  • PC12 Cells
  • Phosphatidylinositol Phosphates / metabolism
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
  • Phosphoric Monoester Hydrolases / metabolism
  • Phosphoric Monoester Hydrolases / physiology*
  • Rats
  • cdc42 GTP-Binding Protein / metabolism
  • rac1 GTP-Binding Protein / metabolism

Substances

  • Phosphatidylinositol Phosphates
  • phosphatidylinositol 3,4,5-triphosphate
  • Nerve Growth Factor
  • Phosphoric Monoester Hydrolases
  • Inositol Polyphosphate 5-Phosphatases
  • Inppl1 protein, rat
  • Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases
  • Rac1 protein, rat
  • cdc42 GTP-Binding Protein
  • rac1 GTP-Binding Protein