Phosphatidylinositol 3-kinases regulate ERK and p38 MAP kinases in canine colonic smooth muscle

Ilia A. Yamboliev, Kevin M. Wiesmann, Cherie A. Singer, Jason C. Hedges, William T. Gerthoffer

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


In canine colon, M2/M3 muscarinic receptors are coupled to extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases. We tested the hypothesis that this coupling is mediated by enzymes of the phosphatidylinositol (PI) 3-kinase family. RT-PCR and Western blotting demonstrated expression of two isoforms, PI 3-kinase-α and PI 3-kinase-γ. Muscarinic stimulation of intact muscle strips (10 μM ACh) activated PI 3-kinase-γ, ERK and p38 MAP kinases, and MAP kinase-activated protein kinase-2, whereas PI 3-kinase-α activation was not detected. Wortmannin (25 μM) abolished the activation of PI 3-kinase-γ ERK, and p38 MAP kinases. MAP kinase inhibition was a PI 3-kinase-γ-specific effect, since wortmannin did not inhibit recombinant activated murine ERK2 MAP kinase, protein kinase C, Raf-1, or MAP kinase kinase. In cultured muscle cells, newborn calf serum (3%) activated PI 3-kinase-α and PI 3-kinase-γ isoforms, ERK and p38 MAP kinases, and stimulated chemotactic cell migration. Using wortmannin and LY-294002 to inhibit PI 3-kinase activity and PD-098059 and SB-203580 to inhibit ERK and p38 MAP kinases, we established that these enzymes are functionally important for regulation of chemotactic migration of colonic myocytes.

Original languageEnglish (US)
Pages (from-to)C352-C360
JournalAmerican Journal of Physiology - Cell Physiology
Issue number2 48-2
StatePublished - 2000
Externally publishedYes


  • Cell migration
  • Mitogen-activated protein kinases
  • Muscarinic receptors
  • Phosphatidylinositol 3-kinases
  • Reverse transcriptase-polymerase chain reaction

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


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