Download MendeleyClaudin-9 structures reveal mechanism for toxin-induced gut barrier breakdown.
Vecchio, A.J., Stroud, R.M.(2019) Proc Natl Acad Sci U S A 116: 17817-17824
- PubMed: 31434788
- DOI: https://doi.org/10.1073/pnas.1908929116
- Primary Citation of Related Structures:
6OV2, 6OV3 - PubMed Abstract:
The human pathogenic bacterium Clostridium perfringens secretes an enterotoxin (CpE) that targets claudins through its C-terminal receptor-binding domain (cCpE). Isoform-specific binding by CpE causes dissociation of claudins and tight junctions (TJs), resulting in cytotoxicity and breakdown of the gut epithelial barrier. Here, we present crystal structures of human claudin-9 (hCLDN-9) in complex with cCpE at 3.2 and 3.3 Å. We show that hCLDN-9 is a high-affinity CpE receptor and that hCLDN-9-expressing cells undergo cell death when treated with CpE but not cCpE, which lacks its cytotoxic domain. Structures reveal cCpE-induced alterations to 2 epitopes known to enable claudin self-assembly and expose high-affinity interactions between hCLDN-9 and cCpE that explain isoform-specific recognition. These findings elucidate the molecular bases for hCLDN-9 selective ion permeability and binding by CpE, and provide mechanisms for how CpE disrupts gut homeostasis by dissociating claudins and TJs to affect epithelial adhesion and intercellular transport.
Organizational Affiliation:
Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158.
