The Potato Nucleotide-binding Leucine-rich Repeat (NLR) Immune Receptor Rx1 Is a Pathogen-dependent DNA-deforming Protein

• Published in: The Journal of biological chemistry Vol. 290; no. 41; pp. 24945 - 24960
• Main Authors: Fenyk, Stepan, Townsend, Philip D., Dixon, Christopher H., Spies, Gerhard B., de San Eustaquio Campillo, Alba, Slootweg, Erik J., Westerhof, Lotte B., Gawehns, Fleur K.K., Knight, Marc R., Sharples, Gary J., Goverse, Aska, Pålsson, Lars-Olof, Takken, Frank L.W., Cann, Martin J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 09.10.2015; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; cellular immune response; DNA - chemistry; DNA - metabolism; DNA-binding protein; EPS-2; host-pathogen interaction; Laboratorium voor Nematologie; Laboratory of Nematology; Leucine; Models, Molecular; Molecular Sequence Data; Nod-like receptor (NLR); plant biochemistry; Plant Biology; plant defense; Plant Diseases - virology; Plant Proteins - chemistry; Plant Proteins - metabolism; plant virus; Plant Viruses - physiology; Potato virus X; Protein Structure, Tertiary; Solanum tuberosum; Solanum tuberosum - immunology; Solanum tuberosum - metabolism; Solanum tuberosum - virology; Substrate Specificity; cellular immune response; host-pathogen interaction; DNA-binding protein; plant defense; plant biochemistry; Nod-like receptor (NLR); plant virus
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M115.672121

Plant nucleotide-binding leucine-rich repeat (NLR) proteins enable cells to respond to pathogen attack. Several NLRs act in the nucleus; however, conserved nuclear targets that support their role in immunity are unknown. Previously, we noted a structural homology between the nucleotide-binding domain of NLRs and DNA replication origin-binding Cdc6/Orc1 proteins. Here we show that the NB-ARC (nucleotide-binding, Apaf-1, R-proteins, and CED-4) domain of the Rx1 NLR of potato binds nucleic acids. Rx1 induces ATP-dependent bending and melting of DNA in vitro, dependent upon a functional P-loop. In situ full-length Rx1 binds nuclear DNA following activation by its cognate pathogen-derived effector protein, the coat protein of potato virus X. In line with its obligatory nucleocytoplasmic distribution, DNA binding was only observed when Rx1 was allowed to freely translocate between both compartments and was activated in the cytoplasm. Immune activation induced by an unrelated NLR-effector pair did not trigger an Rx1-DNA interaction. DNA binding is therefore not merely a consequence of immune activation. These data establish a role for DNA distortion in Rx1 immune signaling and define DNA as a molecular target of an activated NLR. Background: Direct targets for plant NLR proteins in immune signaling are largely unknown. Results: The Rx1 NLR protein of potato binds and distorts DNA following pathogen perception, resulting in immune activation. Conclusion: DNA is a direct signaling target for a plant NLR immune receptor. Significance: Plant NLR receptors might regulate immune transcriptional responses by directly interacting with plant chromatin.