Differential regulation of ERK1/2 and p38 MAPK by components of the Rho signaling pathway during Sphingosine-1-Phosphate-Induced smooth muscle cell migration

Irfan I. Galaria, Allison J. Fegley, Suzanne M. Nicholl, Elisa Roztocil, Mark G. Davies

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


To determine the role of rhosignaling in sphingosine-1-phosphate (S-1-P)-induced smooth muscle cell migration. S-1-P is a bioactive sphingolipid released from activated platelets stimulating migration of smooth muscle cells (SMC) in vitro through Gαi G-proteins and MAPK activation. Rho is one of the key small GTPases required for cytoskeletal reorganization and MAPK activation during migration. We hypothesized that S-1-P-stimulated migration is regulated by the rho-signaling pathway. Rat arterial SMCs were cultured in vitro. Linear wound assays of migration were performed in the presence of S-1-P with and without C3 (a rho antagonist) and Y (Y27632, a Rho kinase inhibitor). Western blotting was performed for MEK1-ERK1/2 and MMK3/MKK6-p38 MAPK phosphorylation after stimulation with S-1-P with and without pre-incubation with the inhibitors. Statistics were analyzed by one-way ANOVA. S-1-P stimulated migration of SMCs in a wound assay (2-fold over control; P < 0.01), which was blocked by Rho inhibition (P < 0.05). S-1-P activated rho and induced a time-dependent increase in ERK1/2 and p38 MAPK activation. In the presence of C3, MEK1 and ERK1/2 phosphorylation were significantly decreased, while MKK3/6 and p38 MAPK phosphorylation were unchanged. In contrast, when rho kinase was inhibited, there was an increase in ERK1/2 and a decrease in p38 MAPK phosphorylation. Rho kinase inhibition resulted in a decrease in MEK1/2 and MKK3/6 phosphorylation. S-1-P differentially regulates the MAPK pathway through components of the rho pathway. Rho regulates ERK1/2 activation through MEK1/2, while Rho kinase negatively modulates ERK1/2 in a MEK1/2-independent manner and regulates p38 MAPK through MKK3/6. This is the first description of differential MAPK regulation by a G-protein-coupled receptor through the rho pathway. Understanding signal transduction in SMCs will contribute to the development of molecular therapeutics for intimal hyperplasia.

Original languageEnglish (US)
Pages (from-to)173-179
Number of pages7
JournalJournal of Surgical Research
Issue number2
StatePublished - Dec 2004


  • MAPK
  • migration
  • Rho
  • Rho kinase
  • smooth muscle cells
  • sphingosine-1-phosphate

ASJC Scopus subject areas

  • Surgery


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