Insulin signaling inhibits the 5-HT2C receptor in choroid plexus via MAP kinase

Joyce H. Hurley, Shengwen Zhang, Leighan S. Bye, Mark S. Marshall, Anna A. DePaoli-Roach, Kunliang Guan, Aaron P. Fox, Lei Yu

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

Background: G protein-coupled receptors (GPCRs) interact with heterotrimeric GTP-binding proteins (G proteins) to modulate acute changes in intracellular messenger levels and ion channel activity. In contrast, long-term changes in cellular growth, proliferation and differentiation are often mediated by tyrosine kinase receptors and certain GPCRs by activation of mitogen-activated protein (MAP) kinases. Complex interactions occur between these signaling pathways, but the specific mechanisms of such regulatory events are not well-understood. In particular it is not clear whether GPCRs are modulated by tyrosine kinase receptor-MAP kinase pathways. Results: Here we describe tyrosine kinase receptor regulation of a GPCR via MAP kinase. Insulin reduced the activity of the 5-HT2C receptor in choroid plexus cells which was blocked by the MAP kinase kinase (MEK) inhibitor, PD 098059. We demonstrate that the inhibitory effect of insulin and insulin-like growth factor type 1 (IGF-1) on the 5-HT2C receptor is dependent on tyrosine kinase, RAS and MAP kinase. The effect may be receptor-specific: insulin had no effect on another GPCR that shares the same G protein signaling pathway as the 5-HT2C receptor. This effect is also direct: activated MAP kinase mimicked the effect of insulin, and removing a putative MAP kinase site from the 5-HT2C receptor abolished the effect of insulin. Conclusion: These results show that insulin signaling can inhibit 5-HT2C receptor activity and suggest that MAP kinase may play a direct role in regulating the function of a specific GPCR.

Original languageEnglish (US)
Article number10
JournalBMC Neuroscience
Volume4
DOIs
StatePublished - Jun 9 2003

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Cellular and Molecular Neuroscience

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