Cholinergic stimulation of early growth response-1 DNA binding activity requires protein kinase C and mitogen-activated protein kinase kinase activation and is inhibited by sodium valproate in SH-SY5Y cells

Carol A. Grimes, Richard S. Jope

Research output: Contribution to journalArticle

22 Scopus citations


Activation of muscarinic receptors in human neuroblastoma SH-SY5Y cells with carbachol stimulated a rapid and large increase in early growth response-1 (Egr-1, also called zif268 and NGF1-A) protein levels and DNA binding activity. Egr-1 DNA binding activity was stimulated within 15 min of treatment with carbachol and maintained a maximum 20-fold increase over basal between 1 and 2 h after treatment, and the EC50 was ~1 μM carbachol. Carbachol-stimulated Egr-1 DNA binding activity was dependent on protein kinase C, as it was potently inhibited by GF109203X (IC50 ~0.1 μM) and was reduced by 85 ± 5% by down-regulation of protein kinase C. Inhibitors of increases in intracellular calcium levels reduced carbachol-induced Egr-1 DNA binding activity by 25-35%. Carbachol-stimulated activation of Egr-1 was reduced 35% by genistein, a tyrosine kinase inhibitor, and 60% by PD098059, an inhibitor of mitogen-activated protein kinase kinases 1/2 (MEK1/2) that activates extracellular-regulated kinases 1/2 (ERK1/2). A novel inhibitory action was caused by chronic (7-day) administration of sodium valproate but not by two other bipolar disorder therapeutic agents, lithium and carbamazepine. Valproate treatment reduced carbachol-stimulated Egr-1 DNA binding activity by 60% but did not alter carbachol-induced activation of ERK1/2 or p38 or increases in Egr-1 protein levels. These results reveal that muscarinic receptors activate Egr-1 through a signaling cascade primarily encompassing protein kinase C, MEK1/2, and ERK1/2 and that valproate substantially inhibits Egr-1 DNA branding activity stimulated by carbachol or protein kinase C.

Original languageEnglish (US)
Pages (from-to)1384-1392
Number of pages9
JournalJournal of neurochemistry
Issue number4
StatePublished - Sep 28 1999
Externally publishedYes



  • Bipolar disorder
  • Carbamazepine
  • Early growth response-l
  • Lithium
  • Protein kinase C
  • Sodium valproate

ASJC Scopus subject areas

  • Biochemistry
  • Cellular and Molecular Neuroscience

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