Plant NLR immune receptor Tm-22 activation requires NB-ARC domain-mediated self-association of CC domain

• Published in: PLoS pathogens 2020-04, Vol.16 (4), p.e1008475-e1008475
• Main Authors: Wang, Junzhu, Chen, Tianyuan, Han, Meng, Qian, Lichao, Li, Jinlin, Wu, Ming, Han, Ting, Cao, Jidong, Nagalakshmi, Ugrappa, Rathjen, John P, Hong, Yiguo, Liu, Yule
• Format: Article
• Language: English
• Subjects: Activation; Adenosine triphosphate; Apoptosis; Binding; Bioinformatics; Biology and Life Sciences; Cell death; Cell Membrane - metabolism; Coils; Disease Resistance; Domains; Laboratories; Leucine; Life sciences; Localization; Medicine and Health Sciences; Movement protein; Nicotiana - immunology; Nicotiana - metabolism; Nicotiana - virology; NLR Proteins - immunology; NLR Proteins - metabolism; Nucleotides; Oligomers; Pathogens; Plant biology; Plant Diseases - immunology; Plant Diseases - virology; Plant Immunity; Plant Proteins - immunology; Plant Proteins - metabolism; Plant resistance; Protein Binding; Protein Domains; Protein structure; Proteins; Receptors; Receptors, Immunologic - immunology; Receptors, Immunologic - metabolism; Recognition; Self-association; Signal Transduction; Signaling; Tobacco; Tobacco Mosaic Virus - metabolism; Tobacco Mosaic Virus - pathogenicity; Viruses
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1008475

The nucleotide-binding, leucine-rich repeat-containing (NLR) class of immune receptors of plants and animals recognize pathogen-encoded proteins and trigger host defenses. Although animal NLRs form oligomers upon pathogen recognition to activate downstream signaling, the mechanisms of plant NLR activation remain largely elusive. Tm-22 is a plasma membrane (PM)-localized coiled coil (CC)-type NLR and confers resistance to Tobacco mosaic virus (TMV) by recognizing its viral movement protein (MP). In this study, we found that Tm-22 self-associates upon recognition of MP. The CC domain of Tm-22 is the signaling domain and its function requires PM localization and self-association. The nucleotide-binding (NB-ARC) domain is important for Tm-22 self-interaction and regulates activation of the CC domain through its nucleotide-binding and self-association. (d)ATP binding may alter the NB-ARC conformation to release its suppression of Tm-22 CC domain-mediated cell death. Our findings provide the first example of signaling domain for PM-localized NLR and insight into PM-localized NLR activation.