Separable fragments and membrane tethering of Arabidopsis RIN4 regulate its suppression of PAMP-triggered immunity

Ahmed J. Afzal, Luis da Cunha, David Mackey

Research output: Contribution to journalArticle


RPM1-interacting protein 4 (RIN4) is a multifunctional Arabidopsis thaliana protein that regulates plant immune responses to pathogen-associated molecular patterns (PAMPs) and bacterial type III effector proteins (T3Es). RIN4, which is targeted by multiple defense-suppressing T3Es, provides a mechanistic link between PAMP-triggered immunity (PTI) and effectortriggered immunity and effector suppression of plant defense. Here we report on a structure-function analysis of RIN4- mediated suppression of PTI. Separable fragments of RIN4, including those produced when the T3E AvrRpt2 cleaves RIN4 and each containing a plant-specific nitrate-induced (NOI) domain, suppress PTI. The N-terminal and C-terminal NOIs each contribute to PTI suppression and are evolutionarily conserved. Native RIN4 is anchored to the plasma membrane by C-terminal acylation. Nonmembrane-tethered derivatives of RIN4 activate a cell death response in wild-type Arabidopsis and are hyperactive PTI suppressors in a mutant background that lacks the cell death response. Our results indicate that RIN4 is a multifunctional suppressor of PTI and that a virulence function of AvrRpt2 may include cleaving RIN4 into active defense-suppressing fragments.

Original languageEnglish (US)
Pages (from-to)3798-3811
Number of pages14
JournalPlant Cell
Issue number10
StatePublished - Dec 1 2011


ASJC Scopus subject areas

  • Plant Science
  • Cell Biology

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