Vinculin Phosphorylation at Tyr1065 regulates Vinculin conformation and tension development in Airway smooth muscle tissues

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Abstract

Background: Vinculin assumes a closed inactive or an open talin/actin-binding conformation. During airway smooth muscle contraction, vinculin undergoes Tyr1065 phosphorylation. Results: Tyr 1065 phosphorylation is required for vinculin conformation-sensitive FRET probes in smooth muscle to assume an open conformation and for tension generation. Conclusion: Tyr1065 phosphorylation regulates the ligand-binding function of vinculin in airway smooth muscle. Significance: Tyr1065 phosphorylation enables regulation of vinculin conformation by external stimuli. Vinculin localizes to membrane adhesion junctions in smooth muscle tissues, where its head domain binds to talin and its tail domain binds to filamentous actin, thus linking actin filaments to the extracellular matrix. Vinculin can assume a closed conformation, in which the head and tail domains bind to each other and mask the binding sites for actin and talin, and an open activated conformation that exposes the binding sites for talin and actin. Acetylcholine stimulation of tracheal smooth muscle tissues induces the recruitment of vinculin to the cell membrane and its interaction with talin and actin, which is required for active tension development. Vinculin phosphorylation at Tyr1065 on its C terminus increases concurrently with tension development in tracheal smooth muscle tissues. In the present study, the role of vinculin phosphorylation at Tyr1065 in regulating the conformation and function of vinculin during airway smooth muscle contraction was evaluated. Vinculin constructs with point mutations at Tyr 1065 (vinculin Y1065F and vinculin Y1065E) and vinculin conformation-sensitive FRET probes were expressed in smooth muscle tissues to determine how Tyr1065 phosphorylation affects smooth muscle contraction and the conformation and cellular functions of vinculin. The results show that vinculin phosphorylation at tyrosine 1065 is required for normal tension generation in airway smooth muscle during contractile stimulation and that Tyr1065 phosphorylation regulates the conformation and scaffolding activity of the vinculin molecule. We conclude that the phosphorylation of vinculin at tyrosine 1065 provides a mechanism for regulating the function of vinculin in airway smooth muscle in response to contractile stimulation.

Original languageEnglish (US)
Pages (from-to)3677-3688
Number of pages12
JournalJournal of Biological Chemistry
Volume289
Issue number6
DOIs
StatePublished - Feb 7 2014

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ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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