Salmonella characterization of the type III effector SrfH and proteomic identification of the secretome

Salmonella is a major global pathogen, causing millions of infections and significant mortality, particularly among HIV‑infected individuals in sub‑Saharan Africa. Its virulence depends on effector proteins delivered into host cells by two type III secretion systems (SPI‑1 and SPI‑2). This work shows that the SPI‑2 effector SrfH drives rapid septicemia by interacting with the host protein TRIP6, likely through a c‑Src–dependent pathway. To expand the known effector repertoire, I used two strategies: a transposon‑based reporter system and LC‑MS/MS analysis of proteins secreted under SPI‑2–inducing conditions. Mass spectrometry identified over 200 secreted proteins, including numerous type III substrates and several effectors secreted independently of type III systems. These findings reveal new aspects of Salmonella pathogenesis and highlight additional secretion pathways that warrant future study.