A critical role of the T3SS effector EseJ in intracellular trafficking and replication ofEdwardsiella piscicidain non-phagocytic cells

Abstract

19Edwardsiella piscicida (E. piscicida) is an intracellular pathogen within a broad 20 spectrum of hosts. Essential to E. piscicida virulence is its ability to survive and 21 replicate inside host cells, yet the underlying mechanisms and the nature of the 22 35 Keywords: Edwardsiella piscicida T3SS effector intracellular trafficking 36 Author summary 37 E. piscicida is a facultative intracellular bacterium associated with septicemia and 38 fatal infections in many animals, including fish and humans. However, little is known 39 about its intracellular life, which is important for successful invasion of the host. The 40 present study is the first comprehensive characterization of E. piscicida's intracellular 41 life-style in host cells. Upon internalization, E. piscicida is transiently contained in 42 Rab5-positive vacuoles, but the pathogen prevents further endosome maturation and 43 fusion with lysosomes by utilizing an T3SS effector EseJ. In addition, the bacterium 44creates an specialized replication niche for rapid growth via an interaction with the ER. 45 Our study provides new insights into the strategies used by E. piscicida to successfully 46 establishes an intracellular lifestyle that contributes to its survival and dissemination 47