Mechanosensitive tyrosine phosphorylation of paxillin and focal adhesion kinase in tracheal smooth muscle

Dachun Tang, Dolly Mehta, Susan J. Gunst

Research output: Contribution to journalArticle

136 Scopus citations

Abstract

We investigated the role of the integrin-associated proteins focal adhesion kinase (FAK) and paxillin as mediators of mechanosensitive signal transduction in tracheal smooth muscle. In muscle strips contracted isometrically with ACh, we observed higher levels of tyrosine phosphorylation of FAK and paxillin at the optimal muscle length (L(o)) than at shorter muscle lengths of 0.5 or 0.75 L(o). Paxillin phosphorylation was also length sensitive in muscles activated by K+ depolarization and adjusted rapidly to changes in muscle length imposed after contractile activation by either ACh or K+ depolarization. Ca2+ depletion did not affect the length sensitivity of paxillin and FAK phosphorylation in muscles activated with ACh, indicating that the mechanotransduction process can be mediated by a Ca2+-independent pathway. Since Ca2+depleted muscles do not generate significant active tension, this suggests that the mechanotransduction mechanism is sensitive to muscle length rather than tension. We conclude that FAK and paxillin participate in an integrin-mediated mechanotransduction process in tracheal smooth muscle. We propose that this pathway may initiate alterations in smooth muscle cell structure and contractility via the remodeling of actin filaments and/or via the mechanosensitive regulation of signaling molecules involved in contractile protein activation.

Original languageEnglish (US)
Pages (from-to)C250-C258
JournalAmerican Journal of Physiology - Cell Physiology
Volume276
Issue number1 45-1
DOIs
StatePublished - 1999

Keywords

  • Contractility
  • Cytoskeleton
  • Focal adhesion proteins
  • Length-tension curve
  • Mechanotransduction
  • Signal transduction

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology
  • Physiology (medical)

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