title: The dominant negative ARM domain uncovers multiple functions of PUB13 in Arabidopsis immunity, flowering, and senescence.
abstract: Regulating the intensity and duration of immune responses is crucial to combat infections without deleterious side effects. Arabidopsis FLS2, the receptor for bacterial flagellin, activates immune signalling by association with its partner BAK1. Upon flagellin (flg22) perception, the plant U-box E3 ubiquitin ligases PUB12 and PUB13 complex with FLS2 in a BAK1-dependent manner, and ubiquitinate FLS2 for protein degradation, thereby down-regulating flagellin signalling. Domain deletion analysis indicates that the ARM domain of PUB13 interacts with the FLS2-BAK1 complex and is phosphorylated by BAK1. Overexpression of the PUB13 ARM domain alone inhibits flg22-induced FLS2-PUB13 association and PUB12/13-mediated FLS2 ubiquitination and degradation in Arabidopsis, suggesting that ectopic expression of the ARM domain in planta generates a dominant negative effect via blocking the ubiquitination activity. Similar to the pub12pub13 double mutant, transgenic plants expressing the PUB13 ARM domain display enhanced immune responses compared with wild-type plants. Moreover, PUB13ARM transgenic plants and the pub12pub13 mutant are more sensitive to stress-induced leaf senescence accompanied by elevated expression of stress-induced senescence marker genes. The resemblance between PUB13ARM transgenic plants and the pub12pub13 mutant provides genetic evidence that ectopic expression of the PUB ARM domain serves as an alternative approach to dissect the overlapping functions of closely related PUB genes.
authors: Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA.
authors: Jinggeng
authors: J
authors: Zhou
authors: Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA.
authors: Dongping
authors: D
authors: Lu
authors: Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX 77843, USA.
authors: Guangyuan
authors: G
authors: Xu
authors: Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX 77843, USA Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843, USA.
authors: Scott A
authors: SA
authors: Finlayson
authors: Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX 77843, USA.
authors: Ping
authors: P
authors: He
authors: Institute for Plant Genomics and Biotechnology, Texas A&M University, College Station, TX 77843, USA Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX 77843, USA Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA lshan@tamu.edu.
authors: Libo
authors: L
authors: Shan
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D016922:Cellular Senescence; D005408:Flagellin / Q000378:metabolism; D035264:Flowers / Q000235:genetics* / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D054884:Host-Pathogen Interactions; D009154:Mutation; D010766:Phosphorylation; D057865:Plant Immunity; D030821:Plants, Genetically Modified; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D059748:Proteolysis; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: D029681:Arabidopsis Proteins; D005408:Flagellin; C558941:PUB12 protein, Arabidopsis; C558942:PUB13 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D011494:Protein Kinases; C411853:FLS2 protein, Arabidopsis
keywords: Dominant negative; flowering; phosphorylation; plant–microbe interactions; receptors; senescence; ubiquitination.