Ras/Erk signaling is essential for activation of protein synthesis by Gq protein-coupled receptor agonists in adult cardiomyocytes

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The Gq protein-coupled receptor agonists phenylephrine (PE) and endothelin-1 (ET-1) induce cardiac hypertrophy and stimulate protein synthesis in cardiomyocytes. This study aims to investigate how they activate mRNA translation in adult cardiomyocytes. PE and ET-1 do not activate protein kinase B but stimulate Ras and Erk, and their ability to activate protein synthesis was blocked by inhibition of Ras or MEK and by rapamycin, which inhibits mTOR (mammalian target of rapamycin). These agonists activated ribosomal protein S6 kinase 1 (S6K1) and induced phosphorylation of eIF4E-binding protein-1 (4E-BP1) and its release from elF4E. These effects were blocked by inhibitors of MEK. Furthermore, adenovirus-mediated expression of constitutively-active MEK1 caused activation of S6K1, phosphorylation of 4E-BP1, and activation of protein synthesis in a rapamycin-sensitive manner. Expression of N17Ras inhibited the regulation of S6K1 and protein synthesis by GqPCR agonists. These data point to a signaling pathway involving Ras and MEK that acts, with mTOR, to control regulatory translation factors and activate protein synthesis. This study provides new insights into the mechanisms underlying the stimulation of protein synthesis by hypertrophic agents in heart.

Original languageEnglish
Pages (from-to)821-829
Number of pages9
JournalCirculation Research
Issue number9
Publication statusPublished - 1 Nov 2002
Externally publishedYes


  • Cardiac hypertrophy
  • MEK
  • S6 kinase 1
  • eIF4E-binding protein-1
  • mRNA translation

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

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