Keywords

Cholera toxin; Vibrio cholerae; Hsp90; Protein–protein interaction; Mutagenesis; Host–pathogen interaction.

Abstract

Cholera is currently on its seventh global pandemic, disproportionately affecting developing countries. Vibrio cholerae, the bacterial etiologic agent, is able to cause infection by adhering to intestinal epithelial cells and secreting cholera toxin (CT), an AB-type exotoxin that dysregulates signaling pathways. Previous research by the Teter lab has shown that Hsp90, a host cytosolic chaperone, is required for CT to enter the cytosol where it produces toxic effects. Hsp90 binds to CT at two specific motifs, RPPDEI and LDIAPA. The prolines in the RPPDEI motif are essential for binding, but the proline in the LDIAPA has yet to be explored. In this thesis, I explore the importance of this proline for Hsp90 binding and subsequent toxin activity. A mutant toxin in a plasmid construct with a proline-to-alanine substitution was generated through ‘round-the-horn mutagenesis and compared to the wild-type toxin in terms of efficacy of toxin entry into the cytosol and subsequent intoxication. Assays determining total toxin pools in the cytosol after transfection showed that there is a qualitative decrease in mutant toxin when compared to the wild type toxin. Further assays will determine the importance of this proline on the Hsp90-CT binding, which can be leveraged in the production of new pharmaceuticals.

Thesis Completion Year

2026

Thesis Completion Semester

Spring

Thesis Chair

Teter, Ken

College

College of Medicine

Department

Burnett School of Biomedical Sciences

Thesis Discipline

Molecular Biology

Language

English

Access Status

Open Access

Length of Campus Access

None

Campus Location

Orlando (Main) Campus

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