Clostridium perfringens enterotoxin binds to the second extracellular loop of claudin-3, a tight junction integral membrane protein.
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 1.0x10(8) M(-1). We concluded that the second extracellular loop is the site through which claudin-3 interacts with CPE on the cell surface.
Department of Cell Biology, Kyoto University, Kyoto, Japan.
K
K
Fujita
J
J
Katahira
Y
Y
Horiguchi
N
N
Sonoda
M
M
Furuse
S
S
Tsukita
D000818:Animals; D001665:Binding Sites; D062465:Claudin-3; D003016:Clostridium perfringens / Q000378:metabolism* / Q000472:pathogenicity*; D004768:Enterotoxins / Q000378:metabolism* / Q000633:toxicity; D007739:L Cells; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism; D014162:Transfection
D062465:Claudin-3; C568123:Cldn3 protein, mouse; D004768:Enterotoxins; D008565:Membrane Proteins; D011993:Recombinant Fusion Proteins; C035598:enterotoxin, Clostridium