Cholera toxin is an AB5 toxin secreted by the human pathogen Vibrio cholerae. Cholera toxin binds to, enters, and intoxicates human intestinal epithelial cells, causing the diarrheal disease cholera. Using a metabolically- incorporated photocrosslinking sialic acid analog developed in the prior granting period, we showed that cholera toxin interacts directly with fucosylated glycoproteins displayed on the surface of human colonic epithelial cell lines. Further, host cell surface display of fucose is critical to the ability of cholera toxin to enter and intoxicate host cells. During the upcoming granting period, we will define the fucosylated glycan structures recognized by the B subunit of cholera toxin (CTB). The results of these experiments will provide insight into the molecular basis for human variation in susceptibility to cholera. In addition, information gained in these experiments will be used to design synthetic molecules that can interfere with cholera toxin action and could potentially be used either clinically, either as prophylactics or therapeutics. We will also investigate the relative roles of the two glycan binding pockets on CTB ? the canonical GM1 binding site and the novel fucosylated glycan binding site. We will determine which glycans are bound in each site, how the two binding sites contribute to CT mechanism of action, and whether there is any interplay between the glycan binding sites. Finally, we will explore how receptor identity affects the efficiency of CTB internalization, the endocytic pathway for CTB internalization, and the ability of CT to intoxicate host cells. The results of these experiments will reveal fundamental mechanisms of CT action and may provide new insight into the molecular basis of endocytic mechanism.

Public Health Relevance

The bacteria Vibrio cholerae produce a toxin that binds to and invades human intestinal epithelial cells, causing the profuse diarrhea that characterizes cholera infection. New data indicate that cholera toxin recognizes fucose, a sugar displayed on the surface of host cells. This proposal builds on this new insight to achieve a mechanistic understanding of how cholera toxin intoxicates host cells and to develop molecules that can prevent host cell intoxication.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
Project #
Application #
Study Section
Intercellular Interactions Study Section (ICI)
Program Officer
Barski, Oleg
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Texas Sw Medical Center Dallas
Schools of Medicine
United States
Zip Code
Tanigaki, Keiji; Sacharidou, Anastasia; Peng, Jun et al. (2018) Hyposialylated IgG activates endothelial IgG receptor Fc?RIIB to promote obesity-induced insulin resistance. J Clin Invest 128:309-322
Cervin, Jakob; Wands, Amberlyn M; Casselbrant, Anna et al. (2018) GM1 ganglioside-independent intoxication by Cholera toxin. PLoS Pathog 14:e1006862
Wands, Amberlyn M; Cervin, Jakob; Huang, He et al. (2018) Fucosylated Molecules Competitively Interfere with Cholera Toxin Binding to Host Cells. ACS Infect Dis 4:758-770
Pham, Nam D; Pang, Poh-Choo; Krishnamurthy, Soumya et al. (2017) Effects of altered sialic acid biosynthesis on N-linked glycan branching and cell surface interactions. J Biol Chem 292:9637-9651
McCombs, Janet E; Zou, Chunxia; Parker, Randy B et al. (2016) Enhanced Cross-Linking of Diazirine-Modified Sialylated Glycoproteins Enabled through Profiling of Sialidase Specificities. ACS Chem Biol 11:185-92
McCombs, Janet E; Kohler, Jennifer J (2016) Pneumococcal Neuraminidase Substrates Identified through Comparative Proteomics Enabled by Chemoselective Labeling. Bioconjug Chem 27:1013-22
Nischan, Nicole; Kohler, Jennifer J (2016) Advances in cell surface glycoengineering reveal biological function. Glycobiology 26:789-96
McCombs, Janet E; Diaz, Jason P; Luebke, Kevin J et al. (2016) Glycan specificity of neuraminidases determined in microarray format. Carbohydr Res 428:31-40
Pham, Nam D; Fermaintt, Charles S; Rodriguez, Andrea C et al. (2015) Cellular metabolism of unnatural sialic acid precursors. Glycoconj J 32:515-29
Wands, Amberlyn M; Fujita, Akiko; McCombs, Janet E et al. (2015) Fucosylation and protein glycosylation create functional receptors for cholera toxin. Elife 4:e09545

Showing the most recent 10 out of 21 publications