β-Arrestin-dependent endocytosis of proteinase-activated receptor 2 is required for intracellular targeting of activated ERK1/2

K. A. DeFea, J. Zalevsky, M. S. Thoma, O. Dery, R. D. Mullins, N. W. Bunnett

Research output: Contribution to journalArticlepeer-review

Abstract

Recently, a requirement for β-arrestin-mediated endocytosis in the activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) by several G protein-coupled receptors (GPCRs) has been proposed. However, the importance of this requirement for function of ERK1/2 is unknown. We report that agonists of Gαq-coupled proteinase-activated receptor 2 (PAR2) stimulate formation of a multiprotein signaling complex, as detected by gel filtration, immunoprecipitation and immunofluorescence. The complex, which contains internalized receptor, β-arrestin, raf-1, and activated ERK, is required for ERK1/2 activation. However, ERK1/2 activity is retained in the cytosol and neither translocates to the nucleus nor causes proliferation. In contrast, a mutant PAR2 (PAR2δST363/6A), which is unable to interact with β-arrestin and, thus, does not desensitize or internalize, activates ERK1/2 by a distinct pathway, and fails to promote both complex formation and cytosolic retention of the activated ERK1/2. Whereas wild-type PAR2 activates ERK1/2 by a PKC-dependent and probably a ras-independent pathway, PAR2(δST363/6A) appears to activate ERK1/2 by a ras-dependent pathway, resulting in increased cell proliferation. Thus, formation of a signaling complex comprising PAR2, β-arrestin, raf-1, and activated ERK1/2 might ensure appropriate subcellular localization of PAR2-mediated ERK activity, and thereby determine the mitogenic potential of receptor agonists.

Original languageEnglish (US)
Pages (from-to)1267-1281
Number of pages15
JournalJournal of Cell Biology
Volume148
Issue number6
DOIs
StatePublished - Mar 20 2000

Keywords

  • Cytosol
  • MAP kinase
  • Receptor trafficking
  • Subcellular localization

ASJC Scopus subject areas

  • Cell Biology

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