PHI-1 interacts with the catalytic subunit of myosin light chain phosphatase to produce a Ca2+ independent increase in MLC20 phosphorylation and force in avian smooth muscle

Amr El-Toukhy, Allison M. Given, Ozgur Ogut, Frank V. Brozovich

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

In avian smooth muscles, GTPγS produces a Rho kinase mediated increase in PHI-1 phosphorylation and force, but whether this correlation is causal is unknown. We examined the effect of phosphorylated PHI-1 (P-PHI-1) on force and myosin light chain (MLC20) phosphorylation at a constant [Ca2+]. P-PHI-1, but not PHI-1, increased MLC20 phosphorylation and force, and phosphorylation of PHI-1 increased the interaction of PHI-1 with PP1c. Microcystin induced a dose-dependent reduction in the binding of PHI-1 to PP1c. These results suggest PHI-1 inhibits myosin light chain phosphatase by interacting with the active site of PP1c to produce a Ca2+ independent increase in MLC20 phosphorylation and force.

Original languageEnglish (US)
Pages (from-to)5779-5784
Number of pages6
JournalFEBS Letters
Volume580
Issue number24
DOIs
StatePublished - Oct 16 2006

Keywords

  • Ca sensitization
  • Chicken gizzard
  • MYPT1
  • Myosin light chain phosphatase
  • PHI-1
  • PP1c

ASJC Scopus subject areas

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

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