A conserved threonine residue in the juxtamembrane domain of the XA21 pattern recognition receptor is critical for kinase autophosphorylation and XA21-mediated immunity.

Abstract	Despite the key role that pattern recognition receptors (PRRs) play in regulating immunity in plants and animals, the mechanism of activation of the associated non-arginine-aspartate (non-RD) kinases is unknown. The rice PRR XA21 recognizes the pathogen-associated molecular pattern, Ax21 (activator of XA21-mediated immunity). Here we show that the XA21 juxtamembrane (JM) domain is required for kinase autophosphorylation. Threonine 705 in the XA21 JM domain is essential for XA21 autophosphorylation in vitro and XA21-mediated innate immunity in vivo. The replacement of Thr(705) by an alanine or glutamic acid abolishes XA21 autophosphorylation and eliminates interactions between XA21 and four XA21-binding proteins in yeast and rice. Although threonine residues analogous to Thr(705) of XA21 are present in the JM domains of most RD and non-RD plant receptor-like kinases, this residue is not required for autophosphorylation of the Arabidopsis RD RLK BRI1 (brassinosteroid insensitive 1). The threonine 705 of XA21 is conserved only in the JM domains of plant RLKs but not in those of fly, human, or mouse suggesting distinct regulatory mechanisms. These results contribute to growing knowledge regarding the mechanism by which non-RD RLKs function in plant.
Authors	Xuewei Chen, Mawsheng Chern, Patrick E Canlas, Caiying Jiang, Deling Ruan, Peijian Cao, Pamela C Ronald
Journal	The Journal of biological chemistry (J Biol Chem) Vol. 285 Issue 14 Pg. 10454-63 (Apr 02 2010) ISSN: 1083-351X [Electronic] United States
PMID	20118235 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, U.S. Gov't, Non-P.H.S.)
Chemical References	Arabidopsis Proteins Plant Proteins RNA, Messenger Recombinant Fusion Proteins Xa21 protein, Oryza sativa enhanced green fluorescent protein Green Fluorescent Proteins Threonine Protein Serine-Threonine Kinases
Topics	Amino Acid Sequence Arabidopsis Proteins Blotting, Western Cell Membrane (metabolism) Gene Expression Regulation, Plant Green Fluorescent Proteins Humans Immunity, Innate Immunoprecipitation Molecular Sequence Data Mutagenesis, Site-Directed Oryza (genetics, growth & development, metabolism) Phosphorylation Plant Diseases (immunology, microbiology) Plant Proteins (genetics, metabolism) Plants, Genetically Modified Protein Serine-Threonine Kinases (genetics, metabolism) Protein Structure, Tertiary RNA, Messenger (genetics, metabolism) Recombinant Fusion Proteins (genetics, isolation & purification, metabolism) Reverse Transcriptase Polymerase Chain Reaction Sequence Homology, Amino Acid Threonine (chemistry, genetics, metabolism) Two-Hybrid System Techniques

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.

Realize the full power of the drug-disease research graph!