The second PDZ domain of zonula occludens-1 is dispensable for targeting to connexin 43 gap junctions

Cell Commun Adhes. 2008 May;15(1):55-63. doi: 10.1080/15419060802014370.

Abstract

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Connexin 43 / metabolism*
  • Gap Junctions / metabolism*
  • HeLa Cells
  • Humans
  • Membrane Proteins / physiology*
  • Phosphoproteins / physiology*
  • Protein Structure, Tertiary
  • Protein Transport / physiology
  • Tight Junctions / physiology
  • Zonula Occludens-1 Protein

Substances

  • Connexin 43
  • Membrane Proteins
  • Phosphoproteins
  • TJP1 protein, human
  • Zonula Occludens-1 Protein