Abstract
Nucleotide binding site-leucine-rich repeat (NBS-LRR) proteins mediate pathogen recognition in both mammals and plants. The molecular mechanisms by which pathogen molecules activate NBS-LRR proteins are poorly understood. Here we show that RPS5, a NBS-LRR protein from Arabidopsis, is activated by AvrPphB, a bacterial protease, via an indirect mechanism. When transiently expressed in Nicotiana benthamiana leaves, full-length RPS5 protein triggered programmed cell death, but only when coexpressed with AvrPphB and a second Arabidopsis protein, PBS1, which is a specific substrate of AvrPphB. Using coimmunoprecipitation analysis, we found that PBS1 is in a complex with the N-terminal coiled coil (CC) domain of RPS5 before exposure to AvrPphB. Deletion of the RPS5 LRR domain caused RPS5 to constitutively activate programmed cell death, even in the absence of AvrPphB and PBS1, and this activation depended on both the CC and NBS domains. The LRR and CC domains both coimmunoprecipitate with the NBS domain but not with each other. Thus, the LRR domain appears to function in part to inhibit RPS5 signaling, and cleavage of PBS1 by AvrPphB appears to release RPS5 from this inhibition. An amino acid substitution in the NBS site of RPS5 that is known to inhibit ATP binding in other NBS-LRR proteins blocked activation of RPS5, whereas a substitution thought to inhibit ATP hydrolysis constitutively activated RPS5. Combined, these data suggest that ATP versus ADP binding functions as a molecular switch that is flipped by cleavage of PBS1.
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Claims 8
Claim · model-written summary
RPS5 was activated by AvrPphB through an indirect mechanism.
- Taxon
- Arabidopsis
Arabidopsise0 - Interactor
- bacteriale0pathogen
- Gene
- RPS5e0
- Outcome
- RPS5e0
- Qualifier
- indirect mechanisme0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“RPS5, a NBS-LRR protein from Arabidopsis, is activated by AvrPphB, a bacterial protease, via an indirect mechanism”
Claim · model-written summary
RPS5 triggered programmed cell death only with AvrPphB and PBS1 coexpression in Nicotiana leaves.
- Taxon
- Nicotiana benthamiana
Nicotiana benthamianae0 - Organ / stage
- leavese0
- Treatment
- coexpressed with AvrPphB and a second Arabidopsis protein, PBS1e0
- Gene
- RPS5e0
- Outcome
- programmed cell deathe0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“When transiently expressed in Nicotiana benthamiana leaves, full-length RPS5 protein triggered programmed cell death, but only when coexpressed with AvrPphB and a second Arabidopsis protein, PBS1”
Claim · model-written summary
PBS1 complexed with the RPS5 N-terminal CC domain before AvrPphB exposure.
Not reportedTaxon
Verbatim
e0“PBS1 is in a complex with the N-terminal coiled coil (CC) domain of RPS5 before exposure to AvrPphB”
t0“plant”
Claim · model-written summary
Deleting the RPS5 LRR domain caused constitutive programmed cell death without AvrPphB or PBS1.
- Treatment
- Deletion of the RPS5 LRR domaine0
- Gene
- RPS5e0
- Outcome
- programmed cell deathe0
- Direction
- constitutively activatee0
- Comparator
- absence of AvrPphB and PBS1e0
Not reportedTaxon
Verbatim
e0“Deletion of the RPS5 LRR domain caused RPS5 to constitutively activate programmed cell death, even in the absence of AvrPphB and PBS1”
Claim · model-written summary
Constitutive activation depended on both CC and NBS domains.
Not reportedTaxon
Verbatim
e0“this activation depended on both the CC and NBS domains”
Claim · model-written summary
LRR and CC domains each coprecipitated with the NBS domain, but not with each other.
Not reportedTaxon
Verbatim
e0“The LRR and CC domains both coimmunoprecipitate with the NBS domain but not with each other”
Claim · model-written summary
An RPS5 NBS substitution associated with impaired ATP binding blocked RPS5 activation.
- Treatment
- An amino acid substitution in the NBS site of RPS5e0
- Gene
- RPS5e0
- Outcome
- activation of RPS5e0
- Direction
- blockede0
Not reportedTaxonComparator
Verbatim
e0“An amino acid substitution in the NBS site of RPS5 that is known to inhibit ATP binding in other NBS-LRR proteins blocked activation of RPS5”
Claim · model-written summary
A substitution thought to impair ATP hydrolysis constitutively activated RPS5.
- Treatment
- a substitution thought to inhibit ATP hydrolysise0
- Gene
- RPS5e0
- Outcome
- RPS5e0
- Direction
- constitutively activatede0
Not reportedTaxonComparator
Verbatim
e0“a substitution thought to inhibit ATP hydrolysis constitutively activated RPS5”
The same questions in other papers
Arabidopsis · cytology · Nicotiana benthamianaPositive and negative results
1 in the opposite direction
- negative
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.