Proceedings of the National Academy of Sciences· 2026Q1
Recognition-dependent activation of the Arabidopsis RRS1-R/RPS4 TIR-NLR immune receptor pair
- 5citations
- Q1SCImago
- 2026year
Short summary
The Arabidopsis immune receptor pair RRS1-R/RPS4 forms a stable oligomer that is activated upon effector recognition, not by changes in oligomer size, but by conformational changes relieving inhibition between RPS4 and RRS1 TIR domains.
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Key points
- RPS4 and RRS1 form a stable oligomer that does not change size upon effector recognition.
- Oligomer formation depends on RPS4's nucleotide binding capacity and involves interactions between RPS4 and RRS1 TIR domains.
- RPS4 mutants lacking TIR domain NADase activity still oligomerize, indicating this activity is not required for complex formation.
- Effector recognition induces conformational changes that relieve inhibition between RPS4 and RRS1 TIR domains, enabling RPS4 TIR proximity and NADase activity.
AI-generated from the title and abstract; the full text is not read.
Abstract
Abstract The Arabidopsis TIR-NLR immune receptors RPS4 and RRS1 function together to enable recognition of multiple effector proteins including AvrRps4 and PopP2. We show here that both in the presence and absence of effector, RPS4 and RRS1 form an oligomer that does not change in size upon effector provision. Oligomer formation involves interactions between the RPS4 and RRS1 TIR domains and requires nucleotide binding capacity in RPS4. RPS4 mutants that lose TIR domain NADase activity abrogate immune activation but retain oligomerization. A cysteine residue in the RPS4 LRR domain contributes to oligomer stabilization. We propose that upon effector recognition, conformational changes in the complex relieve inhibition of RPS4 TIR domains by RRS1 TIR domains, enabling proximity between RPS4 TIR domains to create NADase activity.
The authors' abstract, as published at the source. Proceedings of the National Academy of Sciences, 2026 · DOI ↗
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Field: Plant Science
Plant ScienceAgricultural and Biological Sciences