Zonula occludens toxin modulates tight junctions through protein kinase C-dependent actin reorganization, in vitro

Alessio Fasano, Carla Fiorentini, Gianfranco Donelli, Sergio Uzzau, James B. Kaper, Klara Margaretten, Xueda Ding, Stefano Guandalini, Laurie Comstock, Simeon E. Goldblum

Research output: Contribution to journalArticlepeer-review


The intracellular signaling involved in the mechanism of action of zonula occludens toxin (ZOT) was studied using several in vitro and ex vivo models. ZOT showed a selective effect among various cell lines tested, suggesting that it may interact with a specific receptor, whose surface expression on various cells differs. When tested in IEC6 cell monolayers, ZOT-containing supernatants induced a redistribution of the F-actin cytoskeleton. Similar results were obtained with rabbit ileal mucosa, where the reorganization of F-actin paralleled the increase in tissue permeability. In endothelial cells, the cytoskeletal rearrangement involved a decrease of the soluble G-actin pool (-27%) and a reciprocal increase in the filamentous F-actin pool (+22%). This actin polymerization was time- and dose-dependent, and was reversible. Pretreatment with a specific protein kinase C inhibitor, CGP41251, completely abolished the ZOT effects on both tissue permeability and actin polymerization. In IEC6 cells ZOT induced a peak increment of the PKC-α isoform after 3 min incubation. Taken together, these results suggest that ZOT activates a complex intracellular cascade of events that regulate tight junction permeability, probably mimicking the effect of physiologic modulator(s) of epithelial barrier function.

Original languageEnglish
Pages (from-to)710-720
Number of pages11
JournalJournal of Clinical Investigation
Issue number2
Publication statusPublished - Aug 1995


  • Cholera
  • Cytoskeleton
  • Diarrhea
  • Intestine
  • Permeability

ASJC Scopus subject areas

  • Medicine(all)


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