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Vacuolar processing enzyme is essential for mycotoxin-induced cell death in Arabidopsis thaliana.
- Source :
-
The Journal of biological chemistry [J Biol Chem] 2005 Sep 23; Vol. 280 (38), pp. 32914-20. Date of Electronic Publication: 2005 Jul 25. - Publication Year :
- 2005
-
Abstract
- Some compatible pathogens secrete toxins to induce host cell death and promote their growth. The toxin-induced cell death is a pathogen strategy for infection. To clarify the executioner of the toxin-induced cell death, we examined a fungal toxin (fumonisin B1 (FB1))-induced cell death of Arabidopsis plants. FB1-induced cell death was accompanied with disruption of vacuolar membrane followed by lesion formation. The features of FB1-induced cell death were completely abolished in the Arabidopsis vacuolar processing enzyme (VPE)-null mutant, which lacks all four VPE genes of the genome. Interestingly, an inhibitor of caspase-1 abolished FB1-induced lesion formation, as did a VPE inhibitor. The VPE-null mutant had no detectable activities of caspase-1 or VPE in the FB1-treated leaves, although wild-type leaves had the caspase-1 and VPE activities, both of which were inhibited by a caspase-1 inhibitor. gammaVPE is the most essential among the four VPE homologues for FB1-induced cell death in Arabidopsis leaves. Recombinant gammaVPE recognized a VPE substrate with Km = 30.3 microm and a caspase-1 substrate with Km = 44.2 microm, which is comparable with the values for mammalian caspase-1. The gammaVPE precursor was self-catalytically converted into the mature form exhibiting caspase-1 activity. These in vivo and in vitro analyses demonstrate that gammaVPE is the proteinase that exhibits a caspase-1 activity. We show that VPE exhibiting a caspase-1 activity is a key molecule in toxin-induced cell death. Our findings suggest that a susceptible response of toxin-induced cell death is caused by the VPE-mediated vacuolar mechanism similar to a resistance response of hypersensitive cell death (Hatsugai, N., Kuroyanagi, M., Yamada, K., Meshi, T., Tsuda, S., Kondo, M., Nishimura, M., and Hara-Nishimura, I. (2004) Science 305, 855-858).
- Subjects :
- Animals
Apoptosis
Arabidopsis genetics
Arabidopsis metabolism
Caspase Inhibitors
Catalysis
Cell Death
Cysteine Endopeptidases metabolism
Enzyme Inhibitors pharmacology
Fumonisins pharmacology
Genes, Plant
Genome, Plant
Hydrogen-Ion Concentration
Immunoblotting
Insecta
Ions
Kinetics
Microscopy, Electron
Mutation
Plant Physiological Phenomena
Protein Binding
Reverse Transcriptase Polymerase Chain Reaction
Time Factors
Arabidopsis drug effects
Cysteine Endopeptidases physiology
Gene Expression Regulation, Plant
Mycotoxins toxicity
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9258
- Volume :
- 280
- Issue :
- 38
- Database :
- MEDLINE
- Journal :
- The Journal of biological chemistry
- Publication Type :
- Academic Journal
- Accession number :
- 16043487
- Full Text :
- https://doi.org/10.1074/jbc.M504476200