Abstract
Pattern recognition receptors confer plant resistance to pathogen infection by recognizing the conserved pathogen-associated molecular patterns. The cell surface receptor chitin elicitor receptor kinase 1 of Arabidopsis (AtCERK1) directly binds chitin through its lysine motif (LysM)-containing ectodomain (AtCERK1-ECD) to activate immune responses. The crystal structure that we solved of an AtCERK1-ECD complexed with a chitin pentamer reveals that their interaction is primarily mediated by a LysM and three chitin residues. By acting as a bivalent ligand, a chitin octamer induces AtCERK1-ECD dimerization that is inhibited by shorter chitin oligomers. A mutation attenuating chitin-induced AtCERK1-ECD dimerization or formation of nonproductive AtCERK1 dimer by overexpression of AtCERK1-ECD compromises AtCERK1-mediated signaling in plant cells. Together, our data support the notion that chitin-induced AtCERK1 dimerization is critical for its activation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylglucosamine / chemistry
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Acetylglucosamine / metabolism
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Amino Acid Motifs
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Amino Acid Sequence
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Arabidopsis / immunology
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Arabidopsis / metabolism*
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Arabidopsis Proteins / chemistry*
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Binding Sites
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Chitin / chemistry
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Chitin / metabolism*
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Crystallography, X-Ray
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Hydrogen Bonding
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Ligands
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Models, Molecular
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Molecular Sequence Data
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Mutant Proteins / chemistry
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Mutant Proteins / metabolism
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Phosphorylation
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Plants, Genetically Modified
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Protein Multimerization
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Protein Serine-Threonine Kinases / chemistry*
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / metabolism*
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Protein Structure, Tertiary
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Receptors, Pattern Recognition / chemistry*
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Receptors, Pattern Recognition / genetics
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Receptors, Pattern Recognition / metabolism*
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Signal Transduction
Substances
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Arabidopsis Proteins
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Ligands
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Mutant Proteins
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Receptors, Pattern Recognition
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Chitin
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CERK1 protein, Arabidopsis
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Protein Serine-Threonine Kinases
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Acetylglucosamine