Mechanical forces regulate focal adhesion and costamere assembly in cardiac myocytes

Will W. Sharp, David G. Simpson, Thomas K. Borg, Allen M. Samarel, Louis Terracio

Research output: Contribution to journalArticle

Abstract

-To determine whether the formation and maintenance of focal adhesions and costameres in cardiac myocytes are influenced by the mechanical forces that they transmit, we mechanically unloaded these cells by inhibiting their spontaneous contractile activity with the calcium-channel blocker nifedipine (12 μM). Interferencereflection and fluorescence microscopy revealed that within 24 h of arrest, β1-integrin- and vinculin-positive focal adhesions and costameres were disrupted. Loss of mature β1-integrin from the cell surface was observed in cell surfacelabeling experiments and in Western blots. Subjecting nonbeating cells to a 5% static stretch for 24 h resulted in an increase of 21% for β1-integrin and 39% for vinculin. Stretching beating cells resulted in 71 and 9% increases, respectively. Intracellular concentrations of pre-β1 were not affected by contractile activity or by stretch. Our results indicate that mechanical forces stabilize the cellular levels of β1-integrin and vinculin by possibly regulating their association with the formation and maintenance of focal adhesions and costameres. β1-integrin; vinculin

Original languageEnglish (US)
Pages (from-to)H546-H556
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume273
Issue number2
DOIs
StatePublished - 1997

Keywords

  • β-integrin
  • Vinculin

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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