title: Clostridium perfringens enterotoxin interacts with claudins via electrostatic attraction.
abstract: Clostridium perfringens enterotoxin (CPE), a causative agent of food poisoning, is a pore-forming toxin disrupting the selective permeability of the plasma membrane of target cells, resulting in cell death. We previously identified claudin as the cell surface receptor for CPE. Claudin, a component of tight junctions, is a tetratransmembrane protein and constitutes a large family of more than 20 members, not all of which serve as the receptor for CPE. The mechanism by which the toxin distinguishes the sensitive claudins is unknown. In this study, we localized the region of claudin responsible for interaction with CPE to the C-terminal part of the second extracellular loop and found that the isoelectric point of this region in sensitive claudins was higher than insensitive claudins. Amino acid substitutions to lower the pI resulted in reduced sensitivity to CPE among sensitive claudins, whereas substitutions to raise the pI endowed CPE-insensitive claudins with sensitivity. The steric structure of the claudin-binding domain of CPE reveals an acidic cleft surrounded by Tyr(306), Tyr(310), Tyr(312), and Leu(315), which were reported to be essential for interaction with the sensitive claudins. These results imply that an electrostatic attraction between the basic claudin region and the acidic CPE cleft is involved in their interaction.
authors.affiliation: Department of Molecular Bacteriology, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Kimura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Abe
authors.forename: Shigeki
authors.initials: S
authors.lastname: Kamitani
authors.forename: Hirono
authors.initials: H
authors.lastname: Toshima
authors.forename: Aya
authors.initials: A
authors.lastname: Fukui
authors.forename: Masami
authors.initials: M
authors.lastname: Miyake
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Kamata
authors.forename: Yoshiko
authors.initials: Y
authors.lastname: Sugita-Konishi
authors.forename: Shigeki
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Horiguchi
mesh_terms: D000818:Animals; D057167:Claudins / Q000737:chemistry / Q000378:metabolism*; D003016:Clostridium perfringens / Q000737:chemistry*; D004768:Enterotoxins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008958:Models, Molecular; D050505:Mutant Proteins / Q000378:metabolism; D011485:Protein Binding; D017433:Protein Structure, Secondary; D011956:Receptors, Cell Surface / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D055672:Static Electricity
chemical_list: D057167:Claudins; D004768:Enterotoxins; D050505:Mutant Proteins; D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; C035598:enterotoxin, Clostridium