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Updated: Apr 5, 2026

Author Spotlight: Advancements in Understanding and Combatting Shigella Infections
Published on: February 9, 2024
Determinants of Proteolysis and Cell-Binding for the Shigella flexneri Cytotoxin, SigA
Eng Guan Chua1, Keith Al-Hasani2, Martin Scanlon3
1School of Pathology and Laboratory Medicine, University of Western Australia, Nedlands, WA, 6009, Australia.
Abstract:
Shigella flexneri secretes an enterotoxic, SPATE family autotransporter (AT), SigA, which has cytopathic activity towards cultured epithelial cells. Its cytopathic activity is due to its ability to degrade the cytoskeletal protein, α-fodrin. The mechanisms by which AT toxins target cells and tissues differ and the details of how SigA acts are not known. In the current study, the determinants of proteolysis and cell-targeting for SigA were determined. We demonstrate that the SigA passenger or α-domain consists of two functionally distinct domains, designated α1 and α2, which are sufficient to specify proteolytic and cell-binding activities, respectively.
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