A key virulence factor in many bacteria is the injectisome, a needle‑like structure that delivers toxin proteins directly into host cells. This process relies on the virulence‑associated type‑III secretion system (vT3SS), which facilitates export of both toxin proteins and some of the injectisome’s own building blocks. However, it remains unclear how substrate proteins are selected from the vast cytoplasmic pool and directed to the vT3SS. Our research aims to unravel the molecular mechanisms underlying substrate targeting to the vT3SS, focusing on the hypothesis that vT3SS substrates undergo localized transcription and translation.
To investigate this, we utilize genetic engineering combined with advanced microscopy techniques, including epifluorescence, TIRF, iSIM, and STED microscopy. By elucidating these regulatory processes, our work seeks to provide new insights into how bacterial pathogens control the precise timing and localization of virulence factor secretion. Understanding these mechanisms may reveal novel targets for therapeutic intervention, ultimately contributing to strategies for combating Salmonella and other vT3SS‑dependent infections.