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United States Department of Agriculture

Agricultural Research Service

Title: Vpey Exhibits a Caspase-Like Activity That Contributes to Defense Against Pathogens

Authors
item Rojo, Enrique - CSIC MADRID SPAIN
item Martin, Raquel - CSIC MADRID SPAIN
item Carter, Clay - UC RIVERSIDE CA
item Zouhar, Jan - UC RIVERSIDE CA
item Pan, Songqin - UC RIVERSIDE CA
item Plotnikova, Julia - HARVARD MED SCH BOSTON
item Jin, Hailing - ARS-UCB PLNT GENE EXP CTR
item Paneque, Manuel - CSIC MADRID SPAIN
item Sanchez-Serrano, Jose Juan - CSIC MADRID SPAIN
item Baker, Barbara
item Ausubel, Frederick - HARVARD MED SCH BOSTON
item Raikhel, Natasha - UC RIVERSIDE CA

Submitted to: Current Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 13, 2004
Publication Date: November 9, 2004
Citation: Rojo, E., Martin, R., Carter, C., Zouhar, J., Pan, S., Plotnikova, J., Jin, H., Paneque, M., Sanchez-Serrano, J., Baker, B.J., Ausubel, F.M., Raikhel, N.V. 2004. VPEy Exhibits a Caspase-like Activity that Contributes to Defense against Pathogens. Current Biology, 14:1897-1906.

Interpretive Summary: Caspases are a family of aspartate-specific cysteine proteases that play an essential role in initiating and executing programmed cell death (PCD) in metazoans. Caspase-like activities have been shown to be required for the initiation of PCD in plants, but the genes encoding those activities have not been identified. VPE, a cysteine protease, is induced during senescence, a form of PCD in plants, and is localized in precursor protease vesicles and vacuoles, compartments associated with PCD processes in plants. We conclude that VPE is a caspase-like enzyme that has been recruited in plants to regulate vacuole-mediated cell dismantling during cell death, a process that has significant influence in the outcome of a diverse set of plant-pathogen interactions.

Technical Abstract: Caspases are a family of aspartate-specific cysteine proteases that play an essential role in initiating and executing programmed cell death (PCD) in metazoans. Caspase-like activities have been shown to be required for the initiation of PCD in plants, but the genes encoding those activities have not been identified. VPE, a cysteine protease, is induced during senescence, a form of PCD in plants, and is localized in precursor protease vesicles and vacuoles, compartments associated with PCD processes in plants. We show that VPE binds in vivo to a general caspase inhibitor and to caspase-1-specific inhibitors, which block the activity of VPE. A cysteine protease inhibitor, cystatin, accumulates to 20-fold higher levels in vpe mutants. Homologs of cystatin are known to suppress hypersensitive cell death in plant and animal systems. We also report that infection with an avirulent strain of Pseudomonas syringae results in an increase of caspase-1 activity, and this increase is partially suppressed in vpe mutants. Plants overexpressing VPE exhibit a greater amount of ion leakage during infection with P. syringae, suggesting that VPE may regulate cell death progression during plant-pathogen interaction. VPE expression is induced after infection with P. syringae, Botrytis cinerea, and turnip mosaic virus, and knockout of VPE results in increased susceptibility to these pathogens. We conclude that VPE is a caspase-like enzyme that has been recruited in plants to regulate vacuole-mediated cell dismantling during cell death, a process that has significant influence in the outcome of a diverse set of plant-pathogen interactions.

Last Modified: 9/10/2014
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