Understanding campylobacter jejuni cytolethal distending toxin intracellular trafficking, structure function relationships, and host cell interaction

Chen, Henry

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https://hdl.handle.net/2142/125592 Copy

Description

Title

Understanding campylobacter jejuni cytolethal distending toxin intracellular trafficking, structure function relationships, and host cell interaction

Author(s)

Chen, Henry

Issue Date

2024-07-11

Director of Research (if dissertation) or Advisor (if thesis)

Blanke, Steven R

Doctoral Committee Chair(s)

Blanke, Steven R

Committee Member(s)

• Wilson, Brenda A
• Brieher, William M
• Orlean, Peter A

Department of Study

Microbiology

Discipline

Microbiology

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• AB toxin
• cytolethal distending toxin
• protein-protein interactions
• Campylobacter jejuni
• DNA damage
• holotoxin structure
• trafficking

Abstract

Cytolethal distending toxins (CDTs) are intracellular-acting bacterial genotoxins produced by a diverse group of mucocutaneous human pathogens, including Campylobacter jejuni, a major cause of foodborne illnesses in the United States. While CDTs, specifically those generated by C. jejuni (Cj-CDT), are known to play a crucial role in bacterial infection, understanding their mechanisms of action and contribution to pathogenesis remains limited. This thesis aims to elucidate the functions of different subunits within the multimeric Cj-CDT during cellular intoxication. Specifically, our focus is on assessing how these subunits facilitate toxin delivery to the host cell nucleus and the significance of subunit interactions and assembly in toxin functionality. In investigating the intracellular trafficking of Cj-CDT subunits, our research confirms the involvement of the endosome, Golgi apparatus, and endoplasmic reticulum in toxin activity. However, our efforts to delineate the roles and organelle trafficking patterns of individual Cj-Cdt subunits during cellular intoxication have yielded inconclusive results. To further explore the importance of subunit interaction and assembly in Cj-CDT function, we conducted concentration-dependent analyses of subunit interactions and toxin cellular activity using various experimental techniques. Our findings suggest that at minimal toxin concentrations necessary for cell cycle arrest, mixtures of Cj-CdtA, Cj-CdtB, and Cj-CdtC predominantly exist as non-interacting subunit monomers. This discrepancy between toxin structure and cellular activity challenges the prevailing notion that CDTs primarily intoxicate host cells through preassembled heterotrimeric structures, warranting a reassessment of this model. Finally, we present preliminary and future investigations to understand host cellular relationships, an important gap in knowledge that needs to be addressed in order to advance our understanding of Cj-CDT pathogenesis.

Graduation Semester

2024-08

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/125592

Copyright and License Information

Copyright 2024 Henry Chen

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