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Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
09:18

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

Published on: December 27, 2016

The anti-apoptotic activity associated with phosphatidylinositol transfer protein alpha activates the MAPK and

Martijn Schenning1, Joachim Goedhart, Theodorus W J Gadella

  • 1Bijvoet Center, Department of Biochemistry of Lipids, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. M.Schenning@Dundee.ac.uk

Biochimica Et Biophysica Acta
|May 27, 2008
PubMed

Insights

Overexpressing phosphatidylinositol transfer protein alpha (PI-TPalpha) in mouse fibroblasts increases anti-apoptotic activity via a cannabinoid 1 (CB1)-like receptor. This activation triggers ERK/MAP kinase and Akt/PKB pathways, enhancing cell survival.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Phosphatidylinositol transfer protein alpha (PI-TPalpha) overexpression in NIH3T3 fibroblasts enhances anti-apoptotic activity.
  • This activity is mediated by a G protein-coupled receptor, likely a cannabinoid 1 (CB1)-like receptor, as indicated by pertussis toxin and rimonabant sensitivity.
  • CB1 receptor expression levels vary among NIH3T3 cell lines: SPIalpha > wtNIH3T3 > SPIbeta.

Purpose of the Study:

  • To elucidate the downstream signaling pathways activated by PI-TPalpha-dependent anti-apoptotic factors.
  • To investigate the role of the CB1-like receptor in mediating these downstream effects.
  • To determine if phospholipase C (PLC) activation is involved in the observed anti-apoptotic signaling.

Main Methods:

  • Western blotting to detect activation of ERK/MAP kinase and Akt/PKB pathways.
  • Confocal laser scanning microscopy to visualize EYFP-ERK2 nuclear translocation.
  • Analysis of YFP-labelled C2-domain of protein kinase C translocation to the plasma membrane.

Main Results:

  • Incubation of SPIbeta cells with PI-TPalpha-dependent factors activated ERK/MAP kinase and Akt/PKB pathways in a CB1 receptor-dependent manner.
  • EYFP-ERK2 translocation to the nucleus confirmed ERK2 activation.
  • Activation of the anti-apoptotic transcription factor NF-kappaB was observed, correlating with increased resistance to UV-induced apoptosis.
  • No evidence of phospholipase C activation was found, as indicated by the lack of YFP-labelled C2-domain translocation.

Conclusions:

  • PI-TPalpha-mediated anti-apoptotic activity in NIH3T3 cells involves the activation of ERK/MAP kinase and Akt/PKB signaling pathways through a CB1-like receptor.
  • This signaling cascade leads to the activation of NF-kappaB and enhanced resistance to apoptosis.
  • The anti-apoptotic effect does not appear to involve phospholipase C activation.

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