Research Article

Ordered Assembly of the Adhesive and Electrochemical Connections within Newly Formed Intercalated Disks in Primary Cultures of Adult Rat Cardiomyocytes

Figure 10

Progressive maturation of the intercalated disk (a)–(e). (a) As cardiomyocytes remodel, N-cadherin (Ncad) distributes diffusely around the cell periphery. (b) When cells contact adjoining cells, desmocollin (Dsc) proteins of the armadillo family including plakoglobin (PG) and plakophillin-2 (PKP2) co-localize with N-cadherin at the cell contact site. (c) The nascent adhesive contacts recruit desmoplakin (DP) and the associated intermediate filaments. (d) After assembly of the adhesive plaque, connexin-43 (Cx43) and ankyrin-G (AnkG), a component of the VGSC, selectively localize to the adhesive contact site. (e) The α subunit of the voltage-gated sodium channel Na is incorporated significantly later into the more mature intercalated disks where they associate with ankyrin-G. The assembly process begins with the clustering of transmembrane adhesive contacts, followed by the recruitment of the plaque proteins and reorganization of the subcortical cytoskeleton. The process culminates with the recruitment of gap junctions and components of the VGSC complex (AnkG and Nav1.5) which are also assembled in a step-wise fashion.
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