Intracellular trafficking of Clostridium perfringens iota-toxin b

Masahiro Nagahama, Mariko Umezaki, Ryo Tashiro, Masataka Oda, Keiko Kobayashi, Masahiro Shibutani, Teruhisa Takagishi, Kazumi Ishidoh, Mitsunori Fukuda, Jun Sakurai

    Research output: Contribution to journalArticlepeer-review

    21 Citations (Scopus)


    Clostridium perfringens iota-toxin is composed of an enzymatic component (Ia) and a binding component (Ib). Ib binds to a cell surface receptor, undergoes oligomerization in lipid rafts, and binds Ia. The resulting complex is then endocytosed. Here, we show the intracellular trafficking of iota-toxin. After the binding of the Ib monomer with cells at 4°C, oligomers of Ib formed at 37°C and later disappeared. Immunofluorescence staining of Ib revealed that the internalized Ib was transported to early endosomes. Some Ib was returned to the plasma membrane through recycling endosomes, whereas the rest was transported to late endosomes and lysosomes for degradation. Degraded Ib was delivered to the plasma membrane by an increase in the intracellular Ca2+ concentration caused by Ib. Bafilomycin A1, an endosomal acidification inhibitor, caused the accumulation of Ib in endosomes, and both nocodazole and colchicine, microtubule-disrupting agents, restricted Ib's movement in the cytosol. These results indicated that an internalized Ia and Ib complex was delivered to early endosomes and that subsequent delivery of Ia to the cytoplasm occurs mainly in early endosomes. Ib was either sent back to the plasma membranes through recycling endosomes or transported to late endosomes and lysosomes for degradation. Degraded Ib was transported to plasma membranes.

    Original languageEnglish
    Pages (from-to)3410-3416
    Number of pages7
    JournalInfection and immunity
    Issue number10
    Publication statusPublished - 2012 Oct

    ASJC Scopus subject areas

    • Parasitology
    • Microbiology
    • Immunology
    • Infectious Diseases


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