Abstract
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 effector-triggered 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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Arabidopsis / genetics
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Arabidopsis / immunology*
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Arabidopsis / metabolism
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Arabidopsis Proteins / chemistry
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Arabidopsis Proteins / genetics
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Arabidopsis Proteins / metabolism*
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Bacterial Proteins / immunology
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Bacterial Proteins / metabolism
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Carrier Proteins / chemistry
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cell Death
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Cell Membrane / metabolism
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Gene Expression Regulation, Plant / physiology
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Intracellular Signaling Peptides and Proteins
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Models, Biological
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Molecular Sequence Data
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Phylogeny
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Plant Diseases / immunology*
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Plant Diseases / microbiology
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Plant Immunity / immunology*
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Plant Leaves
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Plants, Genetically Modified
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Protein Structure, Tertiary
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Pseudomonas syringae / growth & development
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Pseudomonas syringae / immunology
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Pseudomonas syringae / pathogenicity*
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Receptors, Pattern Recognition / metabolism
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Virulence
Substances
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Arabidopsis Proteins
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Bacterial Proteins
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Carrier Proteins
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Intracellular Signaling Peptides and Proteins
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RIN4 protein, Arabidopsis
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Receptors, Pattern Recognition
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avrRpt2 protein, Pseudomonas syringae
Associated data
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GENBANK/ABM30198
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GENBANK/ACJ83941
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GENBANK/CBI35706
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GENBANK/GQ497776
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GENBANK/TC174419