LAUSR

Salmonella enterica, a major cause of gastroenteritis and typhoid fever, hijacks host machinery to invade cells, and replicate within a specialized niche. While some host factors are known, a comprehensive, temporally-resolved understanding of the host-pathogen interface has been hindered by a lack of suitable genome-wide methodologies. To address this, a parallel CRISPR screening platform is developed to identify host determinants for distinct infection stages. An invasion screen captured factors for bacterial entry, while a fitness screen identified factors governing long-term survival. The screens reveal a temporal switch in host dependency, from endosomal trafficking in early infection to cell cycle and DNA damage response pathways governing host cell fitness in long-term infection. Notably, the approach uncovers two novel host factors with stage-specific roles, SORL1 as a mediator of bacterial invasion and ZFYVE19 as a factor supporting intracellular proliferation. Genetic disruption of SORL1 or ZFYVE19 validate these roles, leading to impaired invasion or replication, respectively. Importantly, antibody-mediated blockade of SORL1 effectively prevented Salmonella entry, highlighting it as a novel host-directed therapeutic target. Together, the screening strategy provides a powerful framework for the temporal dissection of host-pathogen interactions, revealing novel biology and promising therapeutic targets.