Identification and functional analysis of autophosphorylation sites in Arabidopsis CERK1
M. SUZUKI (1), S. Kenkichi (2), M. Shibuya (2), H. Shimada (2), N. Motoyama (2), S. Takahashi (2), I. Yoshida (2), M. Ohnishi (2), Y. Ishibashi (2), Z. Fujimoto (3), Y. Desaki (2), H. Kaku (2), K. Kito (2), N. Shibuya (2) (1) Meiji university, Japan; (2) Meiji university, Japan; (3) National Institute of Agrobiological Sciences, Japan

Plants have the ability to induce immune responses against potential pathogens through the recognition of microbe-associated molecular patterns (MAMPs). Chitin is a representative fungal MAMP and induces immune responses through a receptor-like kinase, CERK1, in Arabidopsis. Although autophosphorylation of CERK1 is known to be critical for the activation of downstream signaling, little is known about the function of phosphorylation events in the activation of CERK1 as well as the regulation of immune responses. We identified 41 in vitro and 15 in vivo autophosphorylation sites in the CERK1 kinase domain expressed in E.coli or N. benthamiana by MS/MS analysis. Complementation of cerk1 mutant with correspondingly mutated cerk1 indicated that the mutation of several phosphorylation sites were critical for chitin signaling. We confirmed that the mutation of T479A completely abolished CERK1 kinase activity and the ability to complement cerk1 mutant. Mutation of T573A also affected CERK1 kinase activity and the chitin responses. On the other hand, mutation of some other phosphorylation sites affected the biological function of CERK1 without significant effect on the in vitro kinase activity. 

Abstract Number: P17-620
Session Type: Poster