Abstract
CTR1 encodes a negative regulator of the ethylene response pathway in Arabidopsis thaliana. The C-terminal domain of CTR1 is similar to the Raf family of protein kinases, but its first two-thirds encodes a novel protein domain. We used a variety of approaches to investigate the function of these two CTR1 domains. Recombinant CTR1 protein was purified from a baculoviral expression system, and shown to possess intrinsic Ser/Thr protein kinase activity with enzymatic properties similar to Raf-1. Deletion of the N-terminal domain did not elevate the kinase activity of CTR1, indicating that, at least in vitro, this domain does not autoinhibit kinase function. Molecular analysis of loss-of-function ctr1 alleles indicated that several mutations disrupt the kinase catalytic domain, and in vitro studies confirmed that at least one of these eliminates kinase activity, which indicates that kinase activity is required for CTR1 function. One missense mutation, ctr1-8, was found to result from an amino acid substitution within a new conserved motif within the N-terminal domain. Ctr1-8 has no detectable effect on the kinase activity of CTR1 in vitro, but rather disrupts the interaction with the ethylene receptor ETR1. This mutation also disrupts the dominant negative effect that results from overexpression of the CTR1 amino-terminal domain in transgenic Arabidopsis. These results suggest that CTR1 interacts with ETR1 in vivo, and that this association is required to turn off the ethylene-signaling pathway.
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Claims 8
Claim · model-written summary
Recombinant CTR1 showed intrinsic Ser/Thr kinase activity similar to Raf-1.
- Taxon
- Arabidopsis thaliana
Arabidopsis thalianat0 - Gene
- CTR1e0
- Outcome
- intrinsic Ser/Thr protein kinase activitye0
- Comparator
- Raf-1e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Recombinant CTR1 protein was purified from a baculoviral expression system, and shown to possess intrinsic Ser/Thr protein kinase activity with enzymatic properties similar to Raf-1.”
t0“Arabidopsis thaliana”
Claim · model-written summary
Removing the N-terminal domain did not raise CTR1 kinase activity in vitro.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Treatment
- Deletion of the N-terminal domaine0
- Gene
- CTR1e0
- Outcome
- kinase activitye0
- Direction
- did not elevatee0
- Qualifier
- in vitroe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Deletion of the N-terminal domain did not elevate the kinase activity of CTR1, indicating that, at least in vitro, this domain does not autoinhibit kinase function.”
t0“Arabidopsis thaliana”
Claim · model-written summary
Loss-of-function ctr1 mutations disrupted the catalytic domain and one eliminated kinase activity.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- kinase catalytic domaine0
- Outcome
- kinase activitye0
- Direction
- eliminatese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“several mutations disrupt the kinase catalytic domain, and in vitro studies confirmed that at least one of these eliminates kinase activity”
t0“Arabidopsis thaliana”
Claim · model-written summary
The ctr1-8 substitution occurred in a conserved motif in the N-terminal domain.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- ctr1-8e0
- Outcome
- amino acid substitutione0
- Qualifier
- new conserved motif within the N-terminal domaine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“One missense mutation, ctr1-8, was found to result from an amino acid substitution within a new conserved motif within the N-terminal domain.”
t0“Arabidopsis thaliana”
Claim · model-written summary
Ctr1-8 had no detectable effect on CTR1 kinase activity in vitro.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- Ctr1-8e0
- Treatment
- Ctr1-8e0
- Gene
- CTR1e0
- Outcome
- kinase activitye0
- Direction
- no detectable effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ctr1-8 has no detectable effect on the kinase activity of CTR1 in vitro, but rather disrupts the interaction with the ethylene receptor ETR1.”
t0“Arabidopsis thaliana”
Claim · model-written summary
Ctr1-8 disrupted interaction with ETR1.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Material
- Ctr1-8e0
- Gene
- ETR1e0
- Outcome
- interaction with the ethylene receptor ETR1e0
- Direction
- disruptse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Ctr1-8 has no detectable effect on the kinase activity of CTR1 in vitro, but rather disrupts the interaction with the ethylene receptor ETR1.”
t0“Arabidopsis thaliana”
Claim · model-written summary
Ctr1-8 disrupted the dominant negative effect of CTR1 N-terminal overexpression.
- Taxon
- ArabidopsisArabidopsise0
- Treatment
- This mutatione0
- Gene
- CTR1e0
- Outcome
- dominant negative effecte0
- Direction
- disruptse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This mutation also disrupts the dominant negative effect that results from overexpression of the CTR1 amino-terminal domain in transgenic Arabidopsis.”
Claim · model-written summary
The authors infer CTR1–ETR1 interaction is needed to turn off ethylene signaling.
- Taxon
- Arabidopsis thalianaArabidopsis thalianat0
- Gene
- CTR1e0
- Outcome
- ethylene-signaling pathwaye0
- Qualifier
- association is required to turn offe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These results suggest that CTR1 interacts with ETR1 in vivo, and that this association is required to turn off the ethylene-signaling pathway.”
t0“Arabidopsis thaliana”
The same questions in other papers
loss of function · physiology: enzyme activity · Arabidopsis thaliana (thale cress)Results agree
6 papers in the same direction as this paper
- no effect
- negative
- negative
3 papers more in this group
See all 7 papers →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.