title: CALCIUM-DEPENDENT PROTEIN KINASE5 Associates with the Truncated NLR Protein TIR-NBS2 to Contribute toexo70B1-Mediated Immunity.
abstract: Calcium-dependent protein kinases (CPKs) function as calcium sensors and play important roles in plant immunity. Loss of function of the exocyst complex subunit EXO70B1 leads to autoimmunity caused by activation of TN2, a truncated Toll/interleukin-1 receptor-nucleotide binding sequence protein. Here we show, based on a screen for suppressors ofexo70B1, thatexo70B1-activated autoimmune responses requireCPK5However, the CPK5 homologs CPK4, CPK6, and CPK11, which were previously reported to function redundantly with CPK5 in effector-triggered immunity, did not contribute toexo70B1-associated phenotypes, indicating that CPK5 plays a unique role in plant immunity. OverexpressingCPK5results in TN2-dependent autoimmunity and enhanced disease resistance, reminiscent of theexo70B1phenotypes. Ectopic expression ofCPK5in theexo70B1mutant led to constitutive CPK5 protein kinase activity, which was not detectable intn2mutants. Furthermore, TN2 interacts with the CPK5 N-terminal variable and kinase domains, stabilizing CPK5 kinase activity in vitro. This work uncovers a direct functional link between an atypical immune receptor and a crucial component of early immune signaling: increased immunity inexo70B1depends on TN2 and CPK5 and, in a positive feedback loop, TN2 keeps CPK5 enzymatically active beyond the initiating stimulus.
authors.affiliation: Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.affiliation: Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Hake
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.|University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Zhao
authors.affiliation: Department of Plant Biochemistry, Dahlem Centre of Plant Sciences, Freie Universität Berlin, 14195 Berlin, Germany.
authors.forename: Tina
authors.identifier: http://orcid.org/0000-0002-0838-0031
authors.initials: T
authors.lastname: Romeis
authors.affiliation: Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Plant Immunity Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China dztang@genetics.ac.cn.|State Key Laboratory of Ecological Control of Fujian-Taiwan Crop Pests, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Dingzhong
authors.identifier: http://orcid.org/0000-0001-8850-8754
authors.initials: D
authors.lastname: Tang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D060467:Disease Resistance / Q000235:genetics / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology; D057865:Plant Immunity / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D033921:Vesicular Transport Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C000589008:EXO70B1 protein, Arabidopsis; D033921:Vesicular Transport Proteins; D011494:Protein Kinases; C508909:CPK11 protein, Arabidopsis; C000595436:CPK4 protein, Arabidopsis; C582964:CPK5 protein, Arabidopsis; C516787:CPK6 protein, Arabidopsis; D017871:Calcium-Calmodulin-Dependent Protein Kinases