Direct Binding of Three Tight Junction-Associated MAGUKs, ZO-1, ZO-2, and ZO-3, with the COOH Termini of Claudins

• Published in: The Journal of cell biology Vol. 147; no. 6; pp. 1351 - 1363
• Main Authors: Itoh, Masahiko, Furuse, Mikio, Morita, Kazumasa, Kubota, Koji, Saitou, Mitinori, Tsukita, Shoichiro
• Format: Journal Article
• Language: English
• Published: United States Rockefeller University Press 13.12.1999; The Rockefeller University Press
• Subjects: Amino Acid Motifs; Amino Acid Sequence; Animals; Carrier Proteins - chemistry; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell biology; Cell membranes; Cells; Cells, Cultured; Claudin-1; Claudins; Complementary DNA; Epithelial cells; Epithelial Cells - cytology; Gene Deletion; Intestines - cytology; L cells; L Cells (Cell Line); Membrane Proteins - chemistry; Membrane Proteins - deficiency; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membranes; Mice; Mice, Knockout; Microfilaments; Models, Biological; Molecular biology; Molecules; Occludin; Original; Phosphoproteins - chemistry; Phosphoproteins - genetics; Phosphoproteins - metabolism; Protein Binding; Proteins; Recombinant Fusion Proteins - chemistry; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Stem cells; Tight junctions; Tight Junctions - chemistry; Tight Junctions - metabolism; Transfection; Zonula Occludens Proteins; Zonula Occludens-1 Protein; Zonula Occludens-2 Protein
• ISSN: 0021-9525; 1540-8140
• DOI: 10.1083/jcb.147.6.1351

ZO-1, ZO-2, and ZO-3, which contain three PDZ domains (PDZ1 to -3), are concentrated at tight junctions (TJs) in epithelial cells. TJ strands are mainly composed of two distinct types of four-transmembrane proteins, occludin, and claudins, between which occludin was reported to directly bind to ZO-1/ZO-2/ZO-3. However, in occludin-deficient intestinal epithelial cells, ZO-1/ZO-2/ZO-3 were still recruited to TJs. We then examined the possible interactions between ZO-1/ZO-2/ZO-3 and claudins. ZO-1, ZO-2, and ZO-3 bound to the COOH-terminal YV sequence of claudin-1 to -8 through their PDZ1 domains in vitro. Then, claudin-1 or -2 was transfected into L fibroblasts, which express ZO-1 but not ZO-2 or ZO-3. Claudin-1 and -2 were concentrated at cell-cell borders in an elaborate network pattern, to which endogenous ZO-1 was recruited. When ZO-2 or ZO-3 were further transfected, both were recruited to the claudin-based networks together with endogenous ZO-1. Detailed analyses showed that ZO-2 and ZO-3 are recruited to the claudin-based networks through PDZ2 (ZO-2 or ZO-3)/PDZ2 (endogenous ZO-1) and PDZ1 (ZO-2 or ZO-3)/COOH-terminal YV (claudins) interactions. In good agreement, PDZ1 and PDZ2 domains of ZO-1/ZO-2/ZO-3 were also recruited to claudin-based TJs, when introduced into cultured epithelial cells. The possible molecular architecture of TJ plaque structures is discussed.