Francisella tularensis, a gramnegative bacterium, is the causative agent of tularemia, a severe zoonotic disease known for its high lethality even with minimal exposure. Recognized by the CDC as a tier one biothreat agent, as it poses a severe potential risk for biological warfare. This resilient bacterium not only establishes a beneficial environment to thrive within macrophage immune cells but also delays apoptosis (natural programmed cell death). Further, Francisella tularensis interferes with the host's signaling system, specifically targeting the MyD88 pathway. This interference hinders the production of cytokines, which play a crucial role in regulating the immune response. Recent studies suggest that this interference in signaling depends on TolC, a protein known for aiding in the release of specific toxins from bacterial cells. BLAST analysis revealed that part of a protein in Francisella tularensis is similar in a pattern (RTX motif) found in FrpC, a protein secreted by Neisseria meningitidis with the help of TolC, characterizing FTL_1123 as a protein of interest. This research investigated the secretion mechanism of the FTL_1123 protein in Francisella tularensis, and found it is secreted through the canonical Type 1 Secretion System (T1SS), located in Escherichia coli. The FTL_1123 protein lacks the complete RTX regions typically associated with T1SS-secreted proteins. This study provides insight into the secretion of Developing the Secretion of the Francisella Tularensis Protein FTL_1123 from Escherichia coli containing the Hemolysin HlyBD Operon Mehek Sawhney FTL_1123 and the role of RTX motifs in T1SSsecreted proteins. These findings enhance our understanding of bacterial virulence and set the way for possible therapeutics that interfere with the bacteria’s ability to form its replicative niches.

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