ZO-1 determines adherens and gap junction localization at intercalated disks.
The disruption of the spatial order of electromechanical junctions at myocyte-intercalated disks (ICDs) is a poorly understood characteristic of many cardiac disease states. Here, in vitro and in vivo evidence is provided that zonula occludens-1 (ZO-1) regulates the organization of gap junctions (GJs) and adherens junctions (AJs) at ICDs. We investigated the contribution of ZO-1 to cell-cell junction localization by expressing a dominant-negative ZO-1 construct (DN-ZO-1) in rat ventricular myocytes (VMs). The expression of DN-ZO-1 in cultured neonatal VMs for 72 h reduced the interaction of ZO-1 and N-cadherin, as assayed by colocalization and coimmunoprecipitation, prompting cytoplasmic internalization of AJ and GJ proteins. DN-ZO-1 expression in adult VMs in vivo also reduced N-cadherin colocalization with ZO-1, a phenomenon not observed when the connexin-43 (Cx43)-ZO-1 interaction was disrupted using a mimetic of the ZO-1-binding ligand from Cx43. DN-ZO-1-infected VMs demonstrated large GJs at the ICD periphery and showed a loss of focal ZO-1 concentrations along plaque edges facing the disk interior. Additionally, there was breakdown of the characteristic ICD pattern of small interior and large peripheral GJs. Continuous DN-ZO-1 expression in VMs over postnatal development reduced ICD-associated Cx43 GJs and increased lateralized and cytoplasmic Cx43. We conclude that ZO-1 regulation of GJ localization is via an association with the N-cadherin multiprotein complex and that this is a key determinant of stable localization of both AJs and GJs at the ICD.
Department of Regenerative Medicine and Cell Biology, Cardiovascular Biology Center, Medical University of South Carolina, 173 Ashley Ave., Charleston, SC, 29425, USA.
Joseph A
JA
Palatinus
Michael P
MP
O'Quinn
Ralph J
RJ
Barker
Brett S
BS
Harris
Jane
J
Jourdan
Robert G
RG
Gourdie
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D022005:Adherens Junctions / Q000648:ultrastructure*; D000818:Animals; D000831:Animals, Newborn; D015820:Cadherins / Q000378:metabolism; D002469:Cell Separation; D002478:Cells, Cultured; D018031:Connexin 43 / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D000229:Dependovirus / Q000235:genetics; D005260:Female; D017629:Gap Junctions / Q000648:ultrastructure*; D005822:Genetic Vectors; D006352:Heart Ventricles / Q000378:metabolism; D007091:Image Processing, Computer-Assisted; D047468:Immunoprecipitation; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D018613:Microscopy, Confocal; D032383:Myocytes, Cardiac / Q000648:ultrastructure*; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D062826:Zonula Occludens-1 Protein
D048868:Adaptor Proteins, Signal Transducing; D015820:Cadherins; D018031:Connexin 43; D008565:Membrane Proteins; C414604:PDZD2 protein, rat; D010750:Phosphoproteins; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein