title: Vinculin directly binds zonula occludens-1 and is essential for stabilizing connexin-43-containing gap junctions in cardiac myocytes.
abstract: Vinculin (Vcl) links actin filaments to integrin- and cadherin-based cellular junctions. Zonula occludens-1 (ZO-1, also known as TJP1) binds connexin-43 (Cx43, 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 Cx43 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, Cx43 and ZO-1 colocalized at the intercalated disc. Loss of cardiomyocyte Vcl caused parallel loss of ZO-1 from intercalated dics. Vcl co-immunoprecipitated Cx43 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 Cx43, 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.
authors.affiliation: Veterans Administration Healthcare San Diego, San Diego, CA 92161, USA.
authors.forename: Alice E
authors.initials: AE
authors.lastname: Zemljic-Harpf
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Godoy
authors.forename: Oleksandr
authors.initials: O
authors.lastname: Platoshyn
authors.forename: Elizabeth K
authors.initials: EK
authors.lastname: Asfaw
authors.forename: Anna R
authors.initials: AR
authors.lastname: Busija
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Domenighetti
authors.forename: Robert S
authors.initials: RS
authors.lastname: Ross
mesh_terms: D000818:Animals; D002450:Cell Communication; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D032383:Myocytes, Cardiac / Q000378:metabolism*; D009336:Necrosis; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D055550:Protein Stability; D021381:Protein Transport; D020798:Two-Hybrid System Techniques; D016596:Vinculin / Q000378:metabolism*; D062826:Zonula Occludens-1 Protein / Q000378:metabolism*
chemical_list: D018031:Connexin 43; C569043:Tjp1 protein, mouse; D062826:Zonula Occludens-1 Protein; D016596:Vinculin; D019869:Phosphatidylinositol 3-Kinases
keywords: Cardiac myocyte; Gap junction; Heart; Vcl; Vinculin; ZO-1; Zonula occludens-1