Clostridium perfringens alpha-toxin recognizes the GM1a-TrkA complex.

Abstract

Clostridium perfringens alpha-toxin is the major virulence factor in the pathogenesis of gas gangrene. Alpha-toxin is a 43-kDa protein with two structural domains; the N-domain contains the catalytic site and coordinates the divalent metal ions, and the C-domain is a membrane-binding site. The role of the exposed loop region (72-93 residues) in the N-domain, however, has been unclear. Here we show that this loop contains a ganglioside binding motif (H … SXWY … G) that is the same motif seen in botulinum neurotoxin and directly binds to a specific conformation of the ganglioside Neu5Acα2-3(Galβ1-3GalNAcβ1-4)Galβ1-4Glcβ1Cer (GM1a) through a carbohydrate moiety. Confocal microscopy analysis using fluorescently labeled BODIPY-GM1a revealed that the toxin colocalized with GM1a and induced clustering of GM1a on the cell membranes. Alpha-toxin was only slightly toxic in β1,4-N-acetylgalactosaminyltransferase knock-out mice, which lack the a-series gangliosides that contain GM1a, but was highly toxic in α2,8-sialyltransferase knock-out mice, which lack both b-series and c-series gangliosides, similar to the control mice. Moreover, experiments with site-directed mutants indicated that Trp-84 and Tyr-85 in the exposed alpha-toxin loop play an important role in the interaction with GM1a and subsequent activation of TrkA. These results suggest that binding of alpha-toxin to GM1a facilitates the activation of the TrkA receptor and induces a signal transduction cascade that promotes the release of chemokines. Therefore, we conclude that GM1a is the primary cellular receptor for alpha-toxin, which can be a potential target for drug developed against this pathogen.

• Authors: Masataka Oda, Michiko Kabura, Teruhisa Takagishi, Ayaka Suzue, Kaori Tominaga, Shiori Urano, Masahiro Nagahama, Keiko Kobayashi, Keiko Furukawa, Koichi Furukawa, Jun Sakurai
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 287 Issue 39 Pg. 33070-9 (Sep 21 2012) ISSN: 1083-351X [Electronic] United States
• PMID: 22847002 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Toxins
• Calcium-Binding Proteins
• Chemokines
• ganglioside GM1alpha
• G(M1) Ganglioside
• N-Acetylgalactosaminyltransferases
• (N-acetylneuraminyl)-galactosylglucosylceramide N-acetylgalactosaminyltransferase
• Sialyltransferases
• Receptor, trkA
• Type C Phospholipases
• alpha toxin, Clostridium perfringens
• beta-D-Galactoside alpha 2-6-Sialyltransferase

Topics

• Amino Acid Motifs
• Amino Acid Substitution
• Animals
• Bacterial Toxins
• Calcium-Binding Proteins
• Cell Line
• Chemokines (genetics, metabolism)
• Clostridium perfringens
• G(M1) Ganglioside (analogs & derivatives, genetics, metabolism)
• Macrophages, Peritoneal (metabolism)
• Mice
• Mice, Knockout
• Mutagenesis, Site-Directed
• N-Acetylgalactosaminyltransferases (genetics, metabolism)
• Protein Structure, Tertiary
• Receptor, trkA (genetics, metabolism)
• Sialyltransferases (genetics, metabolism)
• Type C Phospholipases
• beta-D-Galactoside alpha 2-6-Sialyltransferase