Cellular uptake of the Clostridium perfringens binary iota-toxin
| Autor: | Joachim Behlke, Klaus Aktories, Holger Barth, Dagmar Blöcker |
|---|---|
| Rok vydání: | 2001 |
| Předmět: |
Clostridium perfringens
Immunology Bacterial Toxins Clostridium difficile toxin B medicine.disease_cause Microbiology Microtubules chemistry.chemical_compound AB toxin medicine Animals Chymotrypsin Humans Cells Cultured ADP Ribose Transferases Brefeldin A biology Bafilomycin Cell Polarity Hydrogen-Ion Concentration Molecular biology Molecular Pathogenesis Cytosol Infectious Diseases chemistry Biochemistry Cytoplasm biology.protein Parasitology |
| Zdroj: | Infection and immunity. 69(5) |
| ISSN: | 0019-9567 |
| Popis: | The binary iota-toxin is produced by Clostridium perfringens type E strains and consists of two separate proteins, the binding component iota b (98 kDa) and an actin-ADP-ribosylating enzyme component iota a (47 kDa). Iota b binds to the cell surface receptor and mediates the translocation of iota a into the cytosol. Here we studied the cellular uptake of iota-toxin into Vero cells. Bafilomycin A1, but not brefeldin A or nocodazole, inhibited the cytotoxic effects of iota-toxin, indicating that toxin is translocated from an endosomal compartment into the cytoplasm. Acidification (pH ≤ 5.0) of the extracellular medium enabled iota a to directly enter the cytosol in the presence of iota b. Activation by chymotrypsin induced oligomerization of iota b in solution. An average mass of 530 ± 28 kDa for oligomers was determined by analytical ultracentrifugation, indicating heptamer formation. The entry of iota-toxin into polarized CaCo-2 cells was studied by measuring the decrease in transepithelial resistance after toxin treatment. Iota-toxin led to a significant decrease in resistance when it was applied to the basolateral surface of the cells but not following application to the apical surface, indicating a polarized localization of the iota-toxin receptor. |
| Databáze: | OpenAIRE |
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