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Summary Activation of nucleotide‐binding leucine‐rich repeat receptors (NLRs) results in immunity and a localized cell death. NLR cell death activity requires oligomerization and in some cases plasma membrane (PM) localization. The exact mechanisms underlying PM localization of NLRs lacking predicted transmembrane domains or recognizable lipidation motifs remain elusive.We used confocal microscopy, genetically encoded molecular tools and protein‐lipid overlay assays to determine whether PM localization of members of the Arabidopsis HeLo‐/RPW8‐like domain ‘helper’ NLR (RNL) family is mediated by the interaction with negatively charged phospholipids of the PM.Our results show that PM localization and stability of some RNLs and one CC‐type NLR (CNL) depend on the direct interaction with PM phospholipids. Depletion of phosphatidylinositol‐4‐phosphate from the PM led to a mis‐localization of the analysed NLRs and consequently inhibited their cell death activity. We further demonstrate homo‐ and hetero‐association of members of the RNL family. Our results provide new insights into the molecular mechanism of NLR localization and defines an important role of phospholipids for CNL and RNL PM localization and consequently, for their function.We propose that RNLs interact with anionic PM phospholipids and that RNL‐mediated cell death and immune responses happen at the PM.
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This content will become publicly available on June 4, 2026
Defense-Suppressive Fragments of RIN4 generated by AvrRpt2 Participate in NDR1-dependent Activation of RPS2
Abstract Plant nucleotide-binding, leucine-rich-repeat (NLR) immune receptors recognize pathogen effectors and activate immunity. The NLR RPS2 recognizes AvrRpt2, aPseudomonaseffector that promotes virulence by proteolytically cleaving a membrane-tethered host protein, RIN4. RIN4 cleavage by AvrRpt2 generates fragments that activate RPS2. A model for RPS2 activation by RIN4 destruction is consistent with the ectopic activity of RPS2 in plants lacking RIN4 but does not explain the link between AvrRpt2’s virulence activity and RPS2 activation. We found that non-membrane-tethered RIN4 derivatives are potent cytosolic activators of RPS2. Activation of RPS2 by these RIN4 derivatives, like AvrRpt2-induced activation, and unlike ectopic activation in the absence of RIN4, requires the defense signaling protein NDR1. Cleavage products of RIN4 produced by AvrRpt2 play contrasting roles in the activation of RPS2, with the membrane-tethered C-terminal fragment suppressing RPS2 and the non-membrane-tethered internal fragment, dependent on compatibility with the C-terminal fragment, overcoming its suppression of RPS2. HighlightsNon-membrane tethered derivatives of RIN4 activate RPS2-induced cell deathActivation of RPS2 by non-membrane-tethered derivatives of RIN4 requires NDR1AvrRpt2-induced cleavage fragments of RIN4 play contrasting roles in RPS2 activation
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- Award ID(s):
- 1953509
- PAR ID:
- 10657867
- Publisher / Repository:
- bioRxiv
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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