biostudies-literatureLehman SSNational Institute of Allergy and Infectious DiseasesIntramural NIH HHSEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Heart, Lung, and Blood InstituteNational Institutes of Health114033https://www.ebi.ac.uk/biostudies/studies/S-EPMC11141579biostudies-literatureUnknown43(4)Small GTPases of the Ras subfamily are best known for their role as proto-oncoproteins, while their function during microbial infection has remained elusive. Here, we show that Legionella pneumophila hijacks the small GTPase NRas to the Legionella-containing vacuole (LCV) surface. A CRISPR interference screen identifies a single L. pneumophila effector, DenR (Lpg1909), required for this process. Recruitment is specific for NRas, while its homologs KRas and HRas are excluded from LCVs. The C-terminal hypervariable tail of NRas is sufficient for recruitment, and interference with either NRas farnesylation or S-acylation sites abrogates recruitment. Intriguingly, we detect markers of active NRas signaling on the LCV, suggesting it acts as a signaling platform. Subsequent phosphoproteomics anaCell reportsThe Legionella pneumophila effector DenR hijacks the host NRas proto-oncoprotein to downregulate MAPK signaling.PMC11141579ZIA HD0088931 ZIA HD008893-121 ZIA AI001085-13Tucholski TWilliamson CDAllen MBouchard SJarnik MMachner MPLehman SSEllis NANita-Lazar AfalseThe Legionella pneumophila effector DenR hijacks the host NRas proto-oncoprotein to downregulate MAPK signaling.Small GTPases of the Ras subfamily are best known for their role as proto-oncoproteins, while their function during microbial infection has remained elusive. Here, we show that Legionella pneumophila hijacks the small GTPase NRas to the Legionella-containing vacuole (LCV) surface. A CRISPR interference screen identifies a single L. pneumophila effector, DenR (Lpg1909), required for this process. Recruitment is specific for NRas, while its homologs KRas and HRas are excluded from LCVs. The C-terminal hypervariable tail of NRas is sufficient for recruitment, and interference with either NRas farnesylation or S-acylation sites abrogates recruitment. Intriguingly, we detect markers of active NRas signaling on the LCV, suggesting it acts as a signaling platform. Subsequent phosphoproteomics ana2024-01-01T00:00:00Z2024 Apr2026-06-02T01:41:53.733Z2026-04-13T03:11:58.808ZS-EPMC111415793856881110.1016/j.celrep.2024.114033