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

✍ Scribed by Akihito Inoko; Masahiko Itoh; Atsushi Tamura; Miho Matsuda; Mikio Furuse; Shoichiro Tsukita

• Publisher: John Wiley and Sons
• Year: 2003
• Tongue: English
• Weight: 276 KB
• Volume: 8
• Category: Article
• ISSN: 1356-9597
• DOI: 10.1046/j.1365-2443.2003.00681.x

✦ Synopsis

Abstract

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.