Effect of ethanol on protein kinase Cζ and p70S6 kinase activation by carbachol: a possible mechanism for ethanol-induced inhibition of glial cell proliferation
Article first published online: 25 JUN 2002
Journal of Neurochemistry
Volume 82, Issue 1, pages 38–46, July 2002
How to Cite
Guizzetti, M. and Costa, L. G. (2002), Effect of ethanol on protein kinase Cζ and p70S6 kinase activation by carbachol: a possible mechanism for ethanol-induced inhibition of glial cell proliferation. Journal of Neurochemistry, 82: 38–46. doi: 10.1046/j.1471-4159.2002.00942.x
- Issue published online: 25 JUN 2002
- Article first published online: 25 JUN 2002
- Received December 6, 2001; revised manuscript received March 9, 2002; accepted March 12, 2002.
- astrocytoma cells;
- cell proliferation;
- muscarinic receptors;
The signal transduction pathways that mediate the mitogenic response of muscarinic acetylcholine receptors in astroglial cells have not been fully elucidated. In this study we investigated the activation of p70S6 kinase (p70S6K) by carbachol in 1321 N1 astroctyoma cells. Carbachol induced a dose- and time-dependent activation of p70S6K, as evidenced by increased phosphorylation at Thr-389, Thr-421 and Ser-424, by increased p70S6K activity, and by a shift in its molecular weight. Activation of p70S6K was mediated by M3 muscarinic acetylcholine receptors (mAChRs) and was inhibited by two phosphatidylinositol-3-kinase (PI3-K) inhibitors, by a pseudosubstrate to protein kinase C (PKC) ζ, and by the p70S6K inhibitor rapamycin. Carbachol-induced DNA synthesis was strongly inhibited by rapamycin, suggesting that p70S6K activation plays an important role in carbachol-induced cell proliferation. Ethanol (25–100 mm) has been shown to inhibit carbachol-induced proliferation of astroglial cells. In the same range of concentrations, ethanol also inhibits carbachol-induced activation of PKCζ and of p70S6K. On the other hand, inhibition of PI3-kinase was only observed at higher ethanol concentrations. These results indicate that activation of the PKCζ p70S6K pathway by M3 mAChRs may play a role in the increased DNA synthesis and may represent a target for ethanol-induced inhibition of astroglial cell proliferation.