Entry of oomycete and fungal effectors into plant and animal host cells

Cell Microbiol. 2011 Dec;13(12):1839-48. doi: 10.1111/j.1462-5822.2011.01659.x. Epub 2011 Aug 25.


Fungal and oomycete pathogens cause many destructive diseases of plants and important diseases of humans and other animals. Fungal and oomycete plant pathogens secrete numerous effector proteins that can enter inside host cells to condition susceptibility. Until recently it has been unknown if these effectors enter via pathogen-encoded translocons or via pathogen-independent mechanisms. Here we review recent evidence that many fungal and oomycete effectors enter via receptor-mediated endocytosis, and can do so in the absence of the pathogen. Surprisingly, a large number of these effectors utilize cell surface phosphatidyinositol-3-phosphate (PI-3-P) as a receptor, a molecule previously known only inside cells. Binding of effectors to PI-3-P appears to be mediated by the cell entry motif RXLR in oomycetes, and by diverse RXLR-like variants in fungi. PI-3-P appears to be present on the surface of animal cells also, suggesting that it may mediate entry of effectors of fungal and oomycete animal pathogens, for example, RXLR effectors found in the oomycete fish pathogen, Saprolegnia parasitica. Reagents that can block PI-3-P-mediated entry have been identified, suggesting new therapeutic strategies.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Amino Acid Motifs
  • Animal Diseases / microbiology
  • Animals
  • Cell Membrane / metabolism
  • Endocytosis*
  • Fungal Proteins / metabolism
  • Host-Pathogen Interactions
  • Oomycetes / pathogenicity*
  • Phosphatidylinositol Phosphates / metabolism*
  • Plant Cells / microbiology*
  • Plant Diseases / microbiology
  • Plants / metabolism
  • Plants / microbiology
  • Protein Binding
  • Protein Transport
  • Receptors, Cell Surface / metabolism*


  • Fungal Proteins
  • Phosphatidylinositol Phosphates
  • Receptors, Cell Surface
  • phosphatidylinositol 3-phosphate