Genetic and molecular evidence that the Pseudomonas syringae type III effector protein AvrRpt2 is a cysteine protease.
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.
Axtell
Michael J
MJ
University of California, Berkeley, Department of Plant and Microbial Biology, 111 Koshland Hall, Berkeley, CA 94720, USA.
Chisholm
Stephen T
ST
Dahlbeck
Douglas
D
Staskawicz
Brian J
BJ
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
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