Back to Search
Start Over
Mediation of Elicitin Activity on Tobacco Is Assumed by Elicitin-Sterol Complexes
- Source :
- Molecular Biology of the Cell, Molecular Biology of the Cell, American Society for Cell Biology, 2001, 12, pp.2825-2834, Scopus-Elsevier
- Publication Year :
- 2001
- Publisher :
- American Society for Cell Biology (ASCB), 2001.
-
Abstract
- Elicitins secreted by phytopathogenic Phytophthora spp. are proteinaceous elicitors of plant defense mechanisms and were demonstrated to load, carry, and transfer sterols between membranes. The link between elicitor and sterol-loading properties was assessed with the use of site-directed mutagenesis of the 47 and 87 cryptogein tyrosine residues, postulated to be involved in sterol binding. Mutated cryptogeins were tested for their ability to load sterols, bind to plasma membrane putative receptors, and trigger biological responses. For each mutated elicitin, the chemical characterization of the corresponding complexes with stigmasterol (1:1 stoichiometry) demonstrated their full functionality. However, these proteins were strongly altered in their sterol-loading efficiency, specific binding to high-affinity sites, and activities on tobacco cells. Ligand replacement experiments strongly suggest that the formation of a sterol-elicitin complex is a requisite step before elicitins fasten to specific binding sites. This was confirmed with the use of two sterol-preloaded elicitins. Both more rapidly displaced labeled cryptogein from its specific binding sites than the unloaded proteins. Moreover, the binding kinetics of elicitins are related to their biological effects, which constitutes the first evidence that binding sites could be the biological receptors. The first event involved in elicitin-mediated cell responses is proposed to be the protein loading with a sterol molecule.
- Subjects :
- Models, Molecular
Phytophthora
0106 biological sciences
Time Factors
Protein Conformation
[SDV]Life Sciences [q-bio]
Receptors, Cell Surface
Biology
Models, Biological
01 natural sciences
Article
Host-Parasite Interactions
Fungal Proteins
03 medical and health sciences
Tobacco
Protein Isoforms
Binding site
Receptor
Molecular Biology
ComputingMilieux_MISCELLANEOUS
Cells, Cultured
Plant Diseases
Plant Proteins
030304 developmental biology
0303 health sciences
Binding Sites
Algal Proteins
Cell Membrane
Proteins
Elicitin
Cell Biology
Hydrogen-Ion Concentration
Ligand (biochemistry)
Receptor–ligand kinetics
Sterol
Elicitor
[SDV] Life Sciences [q-bio]
Sterols
Biochemistry
Tyrosine
Calcium
Sterol binding
Protein Binding
010606 plant biology & botany
Subjects
Details
- ISSN :
- 19394586 and 10591524
- Volume :
- 12
- Database :
- OpenAIRE
- Journal :
- Molecular Biology of the Cell
- Accession number :
- edsair.doi.dedup.....6c82e044783b8adf262b9313e6e68974