title: A substrate-inspired probe monitors translocation, activation, and subcellular targeting of bacterial type III effector protease AvrPphB.
abstract: The AvrPphB effector of Pseudomonas syringae is a papain-like protease that is injected into the host plant cell and cleaves specific kinases to disrupt immune signaling. Here, we used the unique substrate specificity of AvrPphB to generate a specific activity-based probe. This probe displays various AvrPphB isoforms in bacterial extracts, upon secretion and inside the host plant. We show that AvrPphB is secreted as a proprotease and that secretion requires the prodomain, but probably does not involve a pH-dependent unfolding mechanism. The prodomain removal is required for the ability of AvrPphB to trigger a hypersensitive cell death in resistant host plants, presumably since processing exposes a hidden acylation site required for subcellular targeting in the host cell. We detected two active isoforms of AvrPphB in planta, of which the major one localizes exclusively to membranes.
authors: Plant Chemetics Laboratory, Max Planck Institute for Plant Breeding Research, 50829 Cologne, Germany.
authors: Haibin
authors: H
authors: Lu
authors: Zheming
authors: Z
authors: Wang
authors: Mohammed
authors: M
authors: Shabab
authors: Julian
authors: J
authors: Oeljeklaus
authors: Steven H
authors: SH
authors: Verhelst
authors: Farnusch
authors: F
authors: Kaschani
authors: Markus
authors: M
authors: Kaiser
authors: Matthew
authors: M
authors: Bogyo
authors: Renier A L
authors: RA
authors: van der Hoorn
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D015335:Molecular Probes / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D044224:Pseudomonas syringae / Q000201:enzymology*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D013379:Substrate Specificity
chemical_list: D001426:Bacterial Proteins; D015335:Molecular Probes; D020033:Protein Isoforms; D011994:Recombinant Proteins; C500179:avrPphB protein, Pseudomonas syringae