title: 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.
abstract: 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 approximately 1 microM carbachol. Carbachol-stimulated Egr-1 DNA binding activity was dependent on protein kinase C, as it was potently inhibited by GF109203X (IC50 approximately 0.1 microM) 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 binding activity stimulated by carbachol or protein kinase C.
authors.affiliation: Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, 35294-0017, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Grimes
authors.forename: R S
authors.initials: RS
authors.lastname: Jope
mesh_terms: D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002217:Carbachol / Q000494:pharmacology; D004273:DNA, Neoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051766:Early Growth Response Protein 1; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D019833:Genistein / Q000494:pharmacology; D006801:Humans; D017874:Immediate-Early Proteins / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D007700:Kinetics; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; D008301:Maleimides / Q000494:pharmacology; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009447:Neuroblastoma; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014635:Valproic Acid / Q000494:pharmacology*
chemical_list: D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; C497325:EGR1 protein, human; D051766:Early Growth Response Protein 1; D004791:Enzyme Inhibitors; D005419:Flavonoids; D017874:Immediate-Early Proteins; D007211:Indoles; D008301:Maleimides; D014157:Transcription Factors; D014635:Valproic Acid; D002217:Carbachol; D019833:Genistein; D011494:Protein Kinases; C482128:MAP2K2 protein, human; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; C070515:bisindolylmaleimide I; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one