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Clostridium perfringens enterotoxin binds to the second extracellular loop of claudin‐3, a tight junction integral membrane protein

2000; Wiley; Volume: 476; Issue: 3 Linguagem: Inglês

10.1016/s0014-5793(00)01744-0

1873-3468

Kohji Fujita, Jun Katahira, Yasuhiko Horiguchi, Noriyuki Sonoda, Mikio Furuse, Shöichiro Tsukita,

Connexins and lens biology

Claudins (claudin‐1 to ‐18) with four transmembrane domains and two extracellular loops constitute tight junction strands. The peptide toxin Clostridium perfringens enterotoxin (CPE) has been shown to bind to claudin‐3 and ‐4, but not to claudin‐1 or ‐2. We constructed claudin‐1/claudin‐3 chimeric molecules and found that the second extracellular loop of claudin‐3 conferred CPE sensitivity on L fibroblasts. Furthermore, overlay analyses revealed that the second extracellular loop of claudin‐3 specifically bound to CPE at the K a value of 1.0×10 8 M −1 . We concluded that the second extracellular loop is the site through which claudin‐3 interacts with CPE on the cell surface.