A Legionella pneumophila Kinase Phosphorylates the Hsp70 Chaperone Family to Inhibit Eukaryotic Protein Synthesis

Cell Host Microbe. 2019 Mar 13;25(3):454-462.e6. doi: 10.1016/j.chom.2019.01.006. Epub 2019 Feb 28.

Abstract

Legionella pneumophila (L.p.), the microbe responsible for Legionnaires' disease, secretes ∼300 bacterial proteins into the host cell cytosol. A subset of these proteins affects a wide range of post-translational modifications (PTMs) to disrupt host cellular pathways. L.p. has 5 conserved eukaryotic-like Ser/Thr effector kinases, LegK1-4 and LegK7, which are translocated during infection. Using a chemical genetic screen, we identified the Hsp70 chaperone family as a direct host target of LegK4. Phosphorylation of Hsp70s at T495 in the substrate-binding domain disrupted Hsp70's ATPase activity and greatly inhibited its protein folding capacity. Phosphorylation of cytosolic Hsp70 by LegK4 resulted in global translation inhibition and an increase in the amount of Hsp70 on highly translating polysomes. LegK4's ability to inhibit host translation via a single PTM uncovers a role for Hsp70 in protein synthesis and directly links it to the cellular translational machinery.

Keywords: Hsp70; Legionella pneumophila; kinase; phosphorylation; translation.

Publication types

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

MeSH terms

  • Eukaryotic Cells / metabolism*
  • Eukaryotic Cells / microbiology
  • HSP70 Heat-Shock Proteins / metabolism*
  • Host-Pathogen Interactions*
  • Legionella pneumophila / enzymology*
  • Legionnaires' Disease / microbiology
  • Phosphorylation
  • Phosphotransferases / metabolism*
  • Protein Biosynthesis*
  • Protein Processing, Post-Translational*
  • Virulence Factors / metabolism

Substances

  • HSP70 Heat-Shock Proteins
  • Virulence Factors
  • Phosphotransferases