Signalling pathway leading to an activation of mitogen-activated protein kinase by stimulating M3 muscarinic receptor

• Published in: Biochemical journal Vol. 337 ( Pt 2); no. 2; pp. 275 - 280
• Main Authors: Kim, J Y, Yang, M S, Oh, C D, Kim, K T, Ha, M J, Kang, S S, Chun, J S
• Format: Journal Article
• Language: English
• Published: England 15-01-1999
• Subjects: Calcium-Calmodulin-Dependent Protein Kinases - metabolism; Carbachol - pharmacology; Enzyme Activation; Humans; Isoenzymes - metabolism; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases; Protein Kinase C - metabolism; Protein Kinase C-epsilon; Proto-Oncogene Proteins c-raf - metabolism; Proto-Oncogene Proteins p21(ras) - metabolism; Receptor, Muscarinic M3; Receptors, Muscarinic - metabolism; Signal Transduction; Tumor Cells, Cultured
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/0264-6021:3370275

The signalling pathway leading to an activation of mitogen-activated protein (MAP) kinase subtypes Erk-1 and -2 upon stimulation of muscarinic receptor with carbachol in human neuroblastoma SK-N-BE2(C) cells was investigated. Carbachol activated Erk-1/-2 by stimulating M3 muscarinic receptor, as determined by specific antagonists for individual muscarinic receptors. The activation of Erk-1/-2 by carbachol was blocked by the inhibition or down-regulation of protein kinase C (PKC). Among the multiple PKC isoforms expressed in SK-N-BE2(C) cells, only PKCepsilon was activated by the treatment of carbachol, and selective down-regulation of PKCepsilon was sufficient to block Erk-1/-2 activation. Carbachol treatment induced activation of the serine/threonine protein kinase Raf, and an inhibition of Raf blocked Erk-1/-2 activation. Ectopic expression of inhibitory small GTPase Ras, RasN17, blocked the carbachol-induced Raf activation without affecting the activation of PKCepsilon, while the inhibition of PKC blocked the Raf activation. Thus, these results suggest that carbachol-induced activation of PKCepsilon mediates Erk-1/-2 activation by a sequential activation of Ras, Raf and MAP kinase kinase.