29-06-2012
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.
Tight packing of the three LysMs in AtCERK1-ECD.
Links：http://www.sciencemag.org/content/336/6085/1160.abstract
