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Crystal structure of the TIR domain from the Arabidopsis thaliana NLR protein SNC1
Structural highlights
FunctionSNC1_ARATH Disease resistance protein of the TIR-NB-LRR-type. Part of the RPP5 locus that contains a cluster of several paralogous disease resistance (R) genes. Resistance proteins guard the plant against pathogens that contain an appropriate avirulence protein via an indirect interaction with this avirulence protein. That triggers a defense system including the hypersensitive response, which restricts the pathogen growth. Regulated by RNA silencing. Expression regulated by MOS1 at chromatin level. Negatively regulated at the transcript level by BON1. Nuclear localization of SNC1 is essential for its activity (PubMed:22454454). ABA deficiency can rescue high-temperature inhibition of SNC1-mediated defense responses (PubMed:22454454).[1] [2] [3] Publication Abstract from PubMedThe self-association of Toll/interleukin-1 receptor/resistance protein (TIR) domains has been implicated in signaling in plant and animal immunity receptors. Structure-based studies identified different TIR-domain dimerization interfaces required for signaling of the plant nucleotide-binding oligomerization domain-like receptors (NLRs) L6 from flax and disease resistance protein RPS4 from Arabidopsis Here we show that the crystal structure of the TIR domain from the Arabidopsis NLR suppressor of npr1-1, constitutive 1 (SNC1) contains both an L6-like interface involving helices alphaD and alphaE (DE interface) and an RPS4-like interface involving helices alphaA and alphaE (AE interface). Mutations in either the AE- or DE-interface region disrupt cell-death signaling activity of SNC1, L6, and RPS4 TIR domains and full-length L6 and RPS4. Self-association of L6 and RPS4 TIR domains is affected by mutations in either region, whereas only AE-interface mutations affect SNC1 TIR-domain self-association. We further show two similar interfaces in the crystal structure of the TIR domain from the Arabidopsis NLR recognition of Peronospora parasitica 1 (RPP1). These data demonstrate that both the AE and DE self-association interfaces are simultaneously required for self-association and cell-death signaling in diverse plant NLRs. Multiple functional self-association interfaces in plant TIR domains.,Zhang X, Bernoux M, Bentham AR, Newman TE, Ve T, Casey LW, Raaymakers TM, Hu J, Croll TI, Schreiber KJ, Staskawicz BJ, Anderson PA, Sohn KH, Williams SJ, Dodds PN, Kobe B Proc Natl Acad Sci U S A. 2017 Feb 3. pii: 201621248. doi:, 10.1073/pnas.1621248114. PMID:28159890[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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