PHI-1 induced enhancement of myosin phosphorylation in chicken smooth muscle

Amr El-Touhky, Allison M. Given, Audrey Cochard, Frank V. Brozovich

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Herein, we provide evidence that in chicken smooth muscle, G-protein stimulation by a Rho-kinase pathway leads to an increase in myosin light chain phosphorylation. Additionally, G-protein stimulation did not increase MYPT1 phosphorylation at Thr695 or Thr850, and CPI-17, was not expressed in chicken smooth muscle. However, PHI-1 was present in chicken smooth muscle tissues. Both agonist and GTPγS stimulation result in an increase in PHI-1 phosphorylation, which is inhibited by inhibitors to both Rho-kinase (Y-27632) and (PKC) GF109203x. These data suggest that PHI-1 may act as a CPI-17 analog in chicken smooth muscle and inhibit myosin phosphatase activity during G-protein stimulation to produce Ca2+ sensitization.

Original languageEnglish (US)
Pages (from-to)4271-4277
Number of pages7
JournalFEBS Letters
Issue number20
StatePublished - Aug 15 2005


  • CPI-17
  • Integrin-linked kinase
  • MYPT1
  • Myosin light chain phosphatase
  • PHI-1
  • Zip kinase

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology


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