Expression and distribution of ZO-3, a tight junction MAGUK protein, in mouse tissues

Genes Cells. 2003 Nov;8(11):837-45. doi: 10.1046/j.1365-2443.2003.00681.x.


Background: Three related MAGUK proteins, ZO-1, ZO-2 and ZO-3, are concentrated at the cytoplasmic surface of tight junctions. However, in contrast to ZO-1/ZO-2, our knowledge of the expression and distribution of ZO-3 is still fragmentary, partly due to a lack of antibodies that specifically distinguish ZO-3 from ZO-1 and ZO-2.

Results: We generated one pAb and one mAb that specifically recognized ZO-3 on Western blotting. The immunofluorescence signals obtained with these antibodies completely disappeared from ZO-1/ZO-2-positive tight junctions in the liver of ZO-3-deficient mice, indicating that the antibodies can be used to localize ZO-3 in various tissues by immunofluorescence microscopy. Immunofluorescence microscopy with these antibodies revealed that ZO-3 was concentrated at tight junctions in various types of epithelium, but not in endothelium or at cadherin-based cell-cell adhesion sites (spot adherens junctions of fibroblasts and intercalated discs of cardiac muscle cells), where ZO-1 and ZO-2 are concentrated.

Conclusions: We conclude that ZO-3 is expressed in a more epithelium-specific manner than ZO-1 and ZO-2. These observations provide for a better understanding of the functions of tight junction-associated MAGUKs.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Monoclonal
  • Blotting, Northern
  • Blotting, Western
  • Carrier Proteins / immunology
  • Carrier Proteins / metabolism*
  • Endothelial Cells / metabolism*
  • Epithelial Cells / metabolism*
  • Glutathione Transferase / metabolism
  • Guanylate Kinases
  • Liver / metabolism*
  • Membrane Proteins / immunology
  • Membrane Proteins / metabolism*
  • Mice
  • Mice, Knockout
  • Microscopy, Fluorescence
  • Nucleoside-Phosphate Kinase / metabolism*
  • Phosphoproteins / metabolism
  • Rabbits
  • Rats
  • Tight Junctions / metabolism*
  • Zonula Occludens Proteins
  • Zonula Occludens-1 Protein
  • Zonula Occludens-2 Protein


  • Antibodies, Monoclonal
  • Carrier Proteins
  • Membrane Proteins
  • Phosphoproteins
  • Tjp1 protein, mouse
  • Tjp1 protein, rat
  • Tjp2 protein, mouse
  • Tjp3 protein, mouse
  • Zonula Occludens Proteins
  • Zonula Occludens-1 Protein
  • Zonula Occludens-2 Protein
  • Glutathione Transferase
  • Nucleoside-Phosphate Kinase
  • Guanylate Kinases