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San Diego, CA, United States

Zemljic-Harpf A.E.,Veterans Administration Healthcare San Diego | Zemljic-Harpf A.E.,University of California at San Diego | Godoy J.C.,Veterans Administration Healthcare San Diego | Godoy J.C.,University of California at San Diego | And 7 more authors.
Journal of Cell Science | Year: 2014

Vinculin (Vcl) links actin filaments to integrin-and cadherin-based cellular junctions. Zonula occludens-1 (ZO-1, also known as TJP1) binds connexin-43 (C×43, also known as GJA1), cadherin and actin. Vcl and ZO-1 anchor the actin cytoskeleton to the sarcolemma. Given that loss of Vcl from cardiomyocytes causes maldistribution of C×43 and predisposes cardiomyocyte-specific Vcl-knockout mice with preserved heart function to arrhythmia and sudden death, we hypothesized that Vcl and ZO-1 interact and that loss of this interaction destabilizes gap junctions. We found that Vcl, C×43 and ZO-1 colocalized at the intercalated disc. Loss of cardiomyocyte Vcl caused parallel loss of ZO-1 from intercalated dics. Vcl coimmunoprecipitated C×43 and ZO-1, and directly bound ZO-1 in yeast two-hybrid studies. Excision of the Vcl gene in neonatal mouse cardiomyocytes caused a reduction in the amount of Vcl mRNA transcript and protein expression leading to (1) decreased protein expression of C×43, ZO-1, talin, and β1D-integrin, (2) reduced PI3K activation, (3) increased activation of Akt, Erk1 and Erk2, and (4) cardiomyocyte necrosis. In summary, this is the first study showing a direct interaction between Vcl and ZO-1 and illustrates how Vcl plays a crucial role in stabilizing gap junctions and myocyte integrity. © 2014. Published by The Company of Biologists Ltd. Source

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