Signaling from the plasma-membrane localized plant immune receptor RPM1 requires self-association of the full-length protein

Farid El Kasmi, Eui Hwan Chung, Ryan G. Anderson, Jinyue Li, Li Wan, Timothy K. Eitas, Zhiyong Gao, Jeffery L. Dangl

Research output: Contribution to journalArticlepeer-review

52 Citations (Scopus)

Abstract

Plants evolved intracellular immune receptors that belong to the NOD-like receptor (NLR) family to recognize the presence of pathogen-derived effector proteins. NLRs possess an N-terminal Toll-like/IL-1 receptor (TIR) or a non-TIR domain [some of which contain coiled coils (CCs)], a central nucleotide-binding (NB-ARC) domain, and a C-terminal leucine-rich repeat (LRR). Activation of NLR proteins results in a rapid and high-amplitude immune response, eventually leading to host cell death at the infection site, the so-called hypersensitive response. Despite their important contribution to immunity, the exact mechanisms of NLR activation and signaling remain unknown and are likely heterogenous. We undertook a detailed structure-function analysis of the plasma membrane (PM)-localized CC NLR Resistance to Pseudomonas syringae pv. maculicola 1 (RPM1) using both stable transgenic Arabidopsis and transient expression in Nicotiana benthamiana. We report that immune signaling is induced only by activated full-length PM-localized RPM1. Our interaction analyses demonstrate the importance of a functional P-loop for in planta interaction of RPM1 with the small host protein RPM1-interacting protein 4 (RIN4), for constitutive preactivation and postactivation self-association of RPM1 and for proper PM localization. Our results reveal an additive effect of hydrophobic conserved residues in the CC domain for RPM1 function and RPM1 self-association and their necessity for RPM1–RIN4 interaction. Thus, our findings considerably extend our understanding of the mechanisms regulating NLR activation at, and signaling from, the PM.

Original languageEnglish
Pages (from-to)E7385-E7394
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number35
DOIs
Publication statusPublished - 2017 Aug 29
Externally publishedYes

Keywords

  • Arabidopsis thaliana
  • Effector-triggered immunity
  • Effector-triggered immunity
  • NLR receptor
  • Oligomerization
  • Plant immunity

ASJC Scopus subject areas

  • General

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