title: Genetic and molecular evidence that the Pseudomonas syringae type III effector protein AvrRpt2 is a cysteine protease.
abstract: Upon delivery to the plant cell during infection, the Pseudomonas syringae effector protein AvrRpt2 undergoes proteolytic processing, enhances pathogen virulence and causes the elimination of the Arabidopsis RIN4 protein. A structure-prediction method was employed in order to investigate possible biochemical functions of AvrRpt2. Results of a secondary structure prediction algorithm suggest that the functional C-terminal portion of AvrRpt2 is a cysteine protease. Mutation of predicted catalytic residues within this portion of AvrRpt2 abolished in planta processing, elimination of Arabidopsis RIN4, and the ability to trigger an RPS2-specific resistance response. These data indicate that AvrRpt2 is most likely a sequence divergent cysteine protease whose activity is required for elimination of RIN4 during infection.
authors.affiliation: University of California, Berkeley, Department of Plant and Microbial Biology, 111 Koshland Hall, Berkeley, CA 94720, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Axtell
authors.forename: Stephen T
authors.initials: ST
authors.lastname: Chisholm
authors.forename: Douglas
authors.initials: D
authors.lastname: Dahlbeck
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Staskawicz
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000276:immunology / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D020134:Catalytic Domain; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D015870:Gene Expression; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017433:Protein Structure, Secondary; D011549:Pseudomonas / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D040681:Structural Homology, Protein; D014169:Transformation, Bacterial / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D047908:Intracellular Signaling Peptides and Proteins; C453279:RIN4 protein, Arabidopsis; C089426:RPS2 protein, Arabidopsis; C420919:avrRpt2 protein, Pseudomonas syringae; D003546:Cysteine Endopeptidases