Chitin-induced dimerization activates a plant immune receptor.
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.
Graduate Program in Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
Tingting
T
Liu
Zixu
Z
Liu
Chuanjun
C
Song
Yunfei
Y
Hu
Zhifu
Z
Han
Ji
J
She
Fangfang
F
Fan
Jiawei
J
Wang
Changwen
C
Jin
Junbiao
J
Chang
Jian-Min
JM
Zhou
Jijie
J
Chai
D000117:Acetylglucosamine / Q000737:chemistry / Q000378:metabolism; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000276:immunology / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002686:Chitin / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006860:Hydrogen Bonding; D008024:Ligands; D008958:Models, Molecular; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D030821:Plants, Genetically Modified; D055503:Protein Multimerization; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051192:Receptors, Pattern Recognition / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D029681:Arabidopsis Proteins; D008024:Ligands; D050505:Mutant Proteins; D051192:Receptors, Pattern Recognition; D002686:Chitin; C525882:CERK1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D000117:Acetylglucosamine