Morgan O’Donnell

Student

Morgan O’Donnell

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Cohort

2017-2018

Biography

Morgan O’Donnell is a junior in the College of Medicine at the University of Central Florida. She is studying Biomedical Sciences under the Molecular Microbiology track and hopes to earn a PhD in systems biology. Her research interests include synthetic biology, molecular biology, and bioinformatics. Currently, Morgan is performing research in Dr. Ken Teter’s lab where she is investigating the mechanism of cholera toxin (CT) disassembly by a chaperone enzyme, protein disulfide isomerase (PDI). Morgan is also a part of the Honors in the Major program at UCF and will defend her thesis on the same topic in fall 2018.

Faculty Mentor

Ken Teter Ph.D.

Undergraduate Major

Biomedical Sciences

Future Plans

Systems biology Ph.D.

Research

The Molecular Mechanism for Cholera Toxin Disassembly by Protein Disulfide Isomerase Cholera is a life threatening diarrheal disease caused by infection with the Vibrio cholerae bacterium. The disease itself is due to colonization of the intestinal lumen by V. cholerae and its production of an AB type cholera toxin (CT). This toxin is part of the AB 5 family of bacterial exotoxins and is characterized by a catalytic A1 subunit, a short linker A2 subunit, and a pentamer of cell-binding B subunits. After its secretion, CT will bind to GM1 gangliosides on the cell surface of intestinal epithelial cells and is then internalized via endocytosis. Following endocytosis, CT moves to the Golgi apparatus and is then directed to the endoplasmic reticulum where it is disassembled. Disassembly of cholera toxin is vital for its toxicity, as the catalytic A1 subunit must be freed from the A2 linker and B pentamer in order to be rendered toxic to the cell. Protein disulfide isomerase (PDI) is a chaperone with oxidoreductase activity that is present in the endoplasmic reticulum and plays the main role in cholera toxin disassembly by reducing the A1-A2 disulfide bridge and separating the A1 subunit from the A2 linker and B pentamer. It has been established that reduction alone is not efficient for CT disassembly, but the exact mechanism which PDI uses to disassemble CT is unknown. Using techniques such as ELISA assays, protease sensitivity assays, and the use of PDI deletion constructs, this project will explore the mechanism of CT disassembly by PDI.

Disciplines

Medicine and Health Sciences

Morgan O’Donnell

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