Systematic Identification of Host Cell Regulators of Legionella pneumophila Pathogenesis Using a Genome-wide CRISPR Screen

Cell Host Microbe. 2019 Oct 9;26(4):551-563.e6. doi: 10.1016/j.chom.2019.08.017. Epub 2019 Sep 17.


During infection, Legionella pneumophila translocates over 300 effector proteins into the host cytosol, allowing the pathogen to establish an endoplasmic reticulum (ER)-like Legionella-containing vacuole (LCV) that supports bacterial replication. Here, we perform a genome-wide CRISPR-Cas9 screen and secondary targeted screens in U937 human monocyte/macrophage-like cells to systematically identify host factors that regulate killing by L. pneumophila. The screens reveal known host factors hijacked by L. pneumophila, as well as genes spanning diverse trafficking and signaling pathways previously not linked to L. pneumophila pathogenesis. We further characterize C1orf43 and KIAA1109 as regulators of phagocytosis and show that RAB10 and its chaperone RABIF are required for optimal L. pneumophila replication and ER recruitment to the LCV. Finally, we show that Rab10 protein is recruited to the LCV and ubiquitinated by the effectors SidC/SdcA. Collectively, our results provide a wealth of previously undescribed insights into L. pneumophila pathogenesis and mammalian cell function.

Keywords: C1ORF43; CRISPR screen; Legionella pneumophila; RAB10; host-pathogen interaction; intracellular bacteria; pathogen; phagocytosis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / metabolism
  • Cell Line
  • Clustered Regularly Interspaced Short Palindromic Repeats / genetics
  • Endoplasmic Reticulum / metabolism
  • Guanine Nucleotide Exchange Factors / genetics
  • Guanine Nucleotide Exchange Factors / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Legionella pneumophila / genetics
  • Legionella pneumophila / pathogenicity*
  • Legionnaires' Disease / pathology*
  • Macrophages / metabolism
  • Macrophages / microbiology
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Mice
  • Phagocytosis / immunology*
  • Proteins / genetics*
  • RAW 264.7 Cells
  • U937 Cells
  • Vacuoles / microbiology*
  • Virulence Factors / genetics
  • rab GTP-Binding Proteins / genetics
  • rab GTP-Binding Proteins / metabolism


  • Bacterial Proteins
  • C1orf43 protein, human
  • Guanine Nucleotide Exchange Factors
  • KIAA1109 protein, human
  • Membrane Proteins
  • Proteins
  • RABIF protein, human
  • SidC protein, Legionella pneumophila
  • Virulence Factors
  • Rab10 protein, human
  • rab GTP-Binding Proteins