The second PDZ domain of zonula occludens-1 is dispensable for targeting to connexin 43 gap junctions.
Zonula occludens (ZO)-1 is emerging as a central player in the control of gap junction (GJ) dynamics. Previously the authors reported that ZO-1 localizes preferentially to the periphery of Cx43 GJs. How ZO-1 arrives at GJ edges is unknown, but this targeting might involve we established interaction between the Cx43 C-terminus and the PDZ2 domain of ZO-1. Here the show that despite blocking the canonical PDZ2-mediated interaction by fusion of GFP to the C-terminus of Cx43, ZO-1 continued to target to domains juxtaposed with the edges of GJs comprised solely of tagged Cx43. This edge-association was not abolished by deletion of PDZ2 from ZO-1, as mutant ZO-1 also targeted to the periphery of GJs composed of either tagged or untagged Cx43. Additionally, ZO-2 was found colocalized with ZO-1 at GJ edges. These data demonstrate that ZO-1 targets to GJ edges independently of several known PDZ2-mediated interactions, including ZO-1 homodimerization, heterodimerization with ZO-2, and direct ZO-1 binding to the C-terminal residues of Cx43.
Hunter
Andrew W
AW
Department of Cell Biology and Anatomy, Cardiovascular Developmental Biology Center, Medical University of South Carolina, Charleston, South Carolina 29425, USA. huntera@musc.edu
Gourdie
Robert G
RG
D018031:Connexin 43 / Q000378:metabolism*; D017629:Gap Junctions / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology*; D010750:Phosphoproteins / Q000502:physiology*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D019108:Tight Junctions / Q000502:physiology; D062826:Zonula Occludens-1 Protein
D018031:Connexin 43; D008565:Membrane Proteins; D010750:Phosphoproteins; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein