A Bacterial Effector Mimics a Host HSP90 Client to Undermine Immunity

Victor A. Lopez, Brenden C. Park, Dominika Nowak, Anju Sreelatha, Patrycja Zembek, Jessie Fernandez, Kelly A. Servage, Marcin Gradowski, Jacek Hennig, Diana R. Tomchick, Krzysztof Pawłowski, Magdalena Krzymowska, Vincent S. Tagliabracci

Research output: Contribution to journalArticlepeer-review


The molecular chaperone HSP90 facilitates the folding of several client proteins, including innate immune receptors and protein kinases. HSP90 is an essential component of plant and animal immunity, yet pathogenic strategies that directly target the chaperone have not been described. Here, we identify the HopBF1 family of bacterial effectors as eukaryotic-specific HSP90 protein kinases. HopBF1 adopts a minimal protein kinase fold that is recognized by HSP90 as a host client. As a result, HopBF1 phosphorylates HSP90 to completely inhibit the chaperone's ATPase activity. We demonstrate that phosphorylation of HSP90 prevents activation of immune receptors that trigger the hypersensitive response in plants. Consequently, HopBF1-dependent phosphorylation of HSP90 is sufficient to induce severe disease symptoms in plants infected with the bacterial pathogen, Pseudomonas syringae. Collectively, our results uncover a family of bacterial effector kinases with toxin-like properties and reveal a previously unrecognized betrayal mechanism by which bacterial pathogens modulate host immunity.

Original languageEnglish
Pages (from-to)205-218.e21
Issue number1
Publication statusPublished - 2019

Subject classification (UKÄ)

  • Cell Biology
  • Immunology

Free keywords

  • chaperone
  • effector
  • HopBF1
  • HSP90
  • immunity
  • kinase
  • phosphorylation
  • Pseudomonas syringae


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