Serotonin 5-HT1A receptor-mediated Erk activation requires calcium/calmodulin-dependent receptor endocytosis.

Published

Journal Article

Many receptors that couple to heterotrimeric guanine nucleotide-binding (G) proteins mediate rapid activation of the mitogen-activated protein kinases, Erk1 and Erk2. The Gi-coupled serotonin (5-hydroxytryptamine (5-HT)) 5-HT1A receptor, heterologously expressed in Chinese hamster ovary or human embryonic kidney 293 cells, mediated rapid activation of Erk1/2 via a mechanism dependent upon both Ras activation and clathrin-mediated endocytosis. This activation was attenuated by chelation of intracellular Ca2+ and Ca2+/calmodulin (CAM) inhibitors or the CAM sequestrant protein calspermin. The CAM-dependent step in the Erk1/2 activation cascade is downstream of Ras activation, because inhibitors of CAM antagonize Erk1/2 activation induced by constitutively activated mutants of Ras and c-Src but not by constitutively activated mutants of Raf and MEK (mitogen and extracellular signal-regulated kinase). Inhibitors of the classical CAM effectors myosin light chain kinase, CAM-dependent protein kinases II and IV, PP2B, and CAM-sensitive phosphodiesterase had no effect upon 5-HT1A receptor-mediated Erk1/2 activation. Because clathrin-mediated endocytosis was required for 5-HT1A receptor-mediated Erk1/2 activation, we postulated a role for CAM in receptor endocytosis. Inhibition of receptor endocytosis by use of sequestration-defective mutants of beta-arrestin1 and dynamin attenuated 5-HT1A receptor-stimulated Erk1/2 activation. Inhibition of CAM prevented agonist-dependent endocytosis of epitope-tagged 5-HT1A receptors. We conclude that CAM-dependent activation of Erk1/2 through the 5-HT1A receptor reflects its role in endocytosis of the receptor, which is a required step in the activation of MEK and subsequently Erk1/2.

Full Text

Duke Authors

Cited Authors

  • Della Rocca, GJ; Mukhin, YV; Garnovskaya, MN; Daaka, Y; Clark, GJ; Luttrell, LM; Lefkowitz, RJ; Raymond, JR

Published Date

  • February 19, 1999

Published In

Volume / Issue

  • 274 / 8

Start / End Page

  • 4749 - 4753

PubMed ID

  • 9988712

Pubmed Central ID

  • 9988712

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.274.8.4749

Language

  • eng

Conference Location

  • United States