Global mapping of Salmonella enterica-host protein-protein interactions during infection

ABSTRACT: Intracellular bacterial pathogens inject a cocktail of effector proteins into host cells to hijack diverse cellular processes and promote their survival and proliferation. Salmonella enterica serovar Typhimurium (STm) uses two Type 3 secretion system (T3SS) to deliver a suite of effector proteins into host cells, however, knowledge of their host-targets remains sparse. To systematically map STm effector-host protein-protein interactions (PPIs) during active infection, we generated a library of 32 STm strains expressing affinity-tagged effector proteins from their endogenous chromosomal loci. Tagged-effector strains were then used to infect macrophages or epithelial cells, and PPIs were detected by Affinity-Purification Quantitative Mass-Spectrometry (AP-QMS) under both native and cross-linking conditions. We recovered 25 previously described effector-host PPIs, along with 421 novel interactions across the two cell lines tested, as well as several effector-effector PPIs. While effectors converged on specific host cellular processes, which varied across cell types, most had multiple host targets. Using reciprocal co-immunoprecipitations, we could validated 13 out of 22 new PPIs, demonstrating an accuracy of at least 59% for the AP-QMS approach. To illustrate the utility of this resource for discovering novel infection biology, we first showed that SseJ and SseL cooperate to control cholesterol transport at the Salmonella Containing Vacuole (SCV) via the Niemann-Pick C1 protein (NPC1). Second, we uncovered that PipB directly binds and recruits the organelle contact site protein PDZD8 to the SCV. Third, we elucidated a novel mechanism whereby the effector kinase SteC promotes host actin bundling, by directly interacting and phosphorylating formin-like proteins. Overall, we provide a systems-wide host-bacterial pathogen physical interactome resource, to our knowledge the first in an infection context, with broad implications for effector function and cooperation.

INSTRUMENT(S): Q Exactive

ORGANISM(S): Homo Sapiens (human) Mus Musculus (mouse)

TISSUE(S): Epithelial Cell, Macrophage

SUBMITTER: Frank Stein  

LAB HEAD: Dr. Athanasios Typas

PROVIDER: PXD018375 | Pride | 2021-06-25

REPOSITORIES: Pride