Differential association modes of the thrombin receptor PAR1 with Gαi1, Gα12, and β-arrestin 1

Mohammed Akli Ayoub, Eric Trinquet, Kevin D.G. Pfleger, Jean Philippe Pin

Research output: Contribution to journalArticlepeer-review

61 Citations (Scopus)


Although many G protein-coupled receptors (GPCRs) are known to activate multiple signaling pathways by coupling to different types of G proteins or by promoting G protein-independent events, how this occurs remains unclear. Using bioluminescence resonance energy transfer and time-resolved fluorescence resonance energy transfer, we provide evidence for protease-activated receptor 1 (PAR1) forming preassembled complexes with Gαi1 but not Gα12. PAR1 activation appears to rapidly induce transient Gαi1 activation (t1/2 = 4.13 s) but late and stable recruitment of Gα12 (t1/2 = 8.8 min) in parallel with β-arrestin 1 (t1/2 = 7.5 min). However, there is no significant difference in the potency of the agonist-dependent response between Gαi1, Gα12, and β-arrestin 1 (EC50 values 0.48, 0.30, and 0.15 nM, respectively). Although it seems β-arrestin 1 is recruited to preassembled PAR1-Gαi1 complexes, this appears unlikely with Gα12, suggesting 2 distinct receptor populations. Of note, we observed a different Gα12 association mode with other GPCRs, indicating that preassembly and association dynamics may be specific properties of a receptor-G protein pair. Furthermore, the Gα C terminus appears to play different roles in the distinct association modes. Consequently, G protein preassembly or recruitment may constitute novel mechanisms for controlling the kinetics and multitude of GPCR signaling pathways.

Original languageEnglish
Pages (from-to)3522-3535
Number of pages14
JournalFASEB Journal
Issue number9
Publication statusPublished - Sept 2010
Externally publishedYes


  • BRET
  • G proteins
  • GPCRs

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics


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