Functional and structural characterization of LysM proteins in interactions between fungi and plants

Abstract

Chitin Chitin/PGN Rice (Oryza sativa) Plasma membrane Chitin FIGURE 1 | Chitin perception systems in rice (Oryza sativa) and Arabidopsis (Arabidopsis thaliana). Rice OsCEBiP, which carries three extracellular LysM domains (M1-M3) and lacks a kinase domain, undergoes homodimerization upon chitin binding, followed by the recruitment of two OsCERK1 molecules that possess three extracellular LysM domains (M1-M3) and active kinase domains to form a receptor complex in a sandwich-like manner. In parallel, the two LysM-containing receptor-like proteins OsLYP4 and OsLYP6 function together with OsCERK1 to respond to chitin and PGN signals. In Arabidopsis two AtLYK5 monomers that carry three extracellular LysMs bind chitin and then form a tetrameric receptor complex by the recruitment of two AtCERK1 molecules that similarly carry three LysMs. All these Arabidopsis proteins carry intracellular kinase domains and red cross indicates an inactive kinase domain.