Keywords

Chlamydia trachomatis; protein effectors; inclusion membrane; CpoS, Rab35; Drosophila melanogaster

Abstract

Chlamydia trachomatis (Ct) is an obligate intracellular bacterial pathogen and the leading bacterial STI in the United States. Ct uses a wide array of secreted protein effectors throughout infection that aid the infectious particles, which are in membrane-bound vacuoles called inclusion membranes. These secreted effectors have many functions including disarming the host cell defenses and preventing early apoptosis. The Ct effector CpoS is found on the inclusion membrane and has been shown to play a role in preventing premature host cell death. Additionally, CpoS binds to the host protein Rab35, a small GTPase involved in vesicle trafficking. How CpoS impacts Rab35 activity has not been determined, as Rab35 has both an active and inactive state. To address this gap, we used Drosophila melanogaster as an in vivo cell biology platform to study CpoS-Rab35 interaction in vivo. Restricted CpoS expression in the Drosophila wing circumvents lethality and results in reduced wing dimensions. We found that the expression of inactive Rab35 (S22N) phenocopies CpoS expression, but not when overexpressing WT Rab35 or expressing active Rab35 Q67L “on” mutant protein. Because these phenotypes look alike, we hypothesized that CpoS promotes the inactive “off” Rab35 state when they interact. To test this, we performed a genetic interaction experiment and simultaneously expressed the strongest and weakest CpoS transgenic lines with each Rab35 mutant (Rab35 Q67L, Rab35 S22N, Rab35 WT). We found that when expressing CpoS and the active/on form of Rab35 (Q67L), the reduced wing phenotype was rescued and resulted in larger wing dimensions. With the co-expression of CpoS and the inactive/off form of Rab35 (S22N), we experienced lethality in the progeny of the cross. These findings give us a better understanding that CpoS may be acting as a GTPase activating protein for Rab35.

Thesis Completion Year

2026

Thesis Completion Semester

Spring

Thesis Chair

Aranjuez, George

College

College of Medicine

Department

Burnett School of Biomedical Sciences

Thesis Discipline

Burnett School of Biomedical Sciences

Access Status

Campus Access

Length of Campus Access

5 years

Campus Location

Orlando (Main) Campus

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Available for download on Thursday, May 15, 2031

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In Copyright