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          Institute: MPI für Pflanzenzüchtungsforschung     Collection: Dept. Plant Microbe Interactions (Paul Schulze-Lefert)     Display Documents

ID: 28806.0, MPI für Pflanzenzüchtungsforschung / Dept. Plant Microbe Interactions (Paul Schulze-Lefert)
Mlo, a modulator of plant defense and cell death, is a novel calmodulin-binding protein - Isolation and characterization of a rice Mlo homologue
Authors:Kim, M. C.; Lee, S. H.; Kim, J. K.; Chun, H. J.; Choi, M. S.; Chung, W. S.; Moon, B. C.; Kang, C. H.; Park, C. Y.; Yoo, J. H.; Kang, Y. H.; Koo, S. C.; Koo, Y. D.; Jung, J. C.; Kim, S. T.; Schulze-Lefert, P.; Lee, S. Y.; Cho, M. J.
Date of Publication (YYYY-MM-DD):2002-05-31
Title of Journal:Journal of Biological Chemistry
Journal Abbrev.:J. Biol. Chem.
Issue / Number:22
Start Page:19304
End Page:19314
Review Status:Peer-review
Audience:Experts Only
Abstract / Description:Transient influx of Ca2+ constitutes an early event in the signaling cascades that trigger plant defense responses. However, the downstream components of defense-associated Ca2+ signaling are largely unknown. Because Ca2+ signals are mediated by Ca2+-binding proteins, including calmodulin (CaM), identification and characterization of CaM-binding proteins elicited by pathogens should provide insights into the mechanism by which Ca2+ regulates defense responses. In this study, we isolated a gene encoding rice Mlo (Oryza sativa Mlo; OsMlo) using a protein-protein interaction-based screening of a cDNA expression library constructed from pathogen-elicited rice suspension cells. OsMlo has a molecular mass of 62 kDa and shares 65% sequence identity and scaffold topology with barley Mlo, a heptahelical transmembrane protein known to function as a negative regulator of broad spectrum disease resistance and leaf cell death. By using gel overlay assays, we showed that OsMlo produced in Escherichia coli binds to soybean CaM isoform-1 (SCaM-1) in a Ca2+-dependent manner. We located a 20- amino acid CaM-binding domain (CaMBD) in the OsMlo C-terminal cytoplasmic tail that is necessary and sufficient for Ca2+- dependent CaM complex formation. Specific binding of the conserved CaMBD to CaM was corroborated by site-directed mutagenesis, a gel mobility shift assay, and a competition assay with a Ca2+/CaM-dependent enzyme. Expression of OsMlo was strongly induced by a fungal pathogen and by plant defense signaling molecules. We propose that binding of Ca2+-loaded CaM to the C-terminal tail may be a common feature of Mlo proteins.
Comment of the Author/Creator:Date: 2002, MAY 31
External Publication Status:published
Document Type:Article
Communicated by:N.N.
Affiliations:MPI für Pflanzenzüchtungsforschung
External Affiliations:Gyeongsang Natl Univ, Div Appl Life Sci, Program BK21, Plant; Mol Biol & Biotechnol Res Ctr, Chinju 660701, South Korea; Gyeongsang Natl Univ, Div Appl Life Sci, Program BK21, Plant Mol Biol & Biotechnol Res Ctr, Chinju 660701, South Korea; Max Planck Inst Zuchtungsforsch, D-50829 Cologne, Germany
Identifiers:ISI:000175894800010 [ID No:1]
ISSN:0021-9258 [ID No:2]
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