CTR1

Summary: CTR1 localizes to the ER receptor signaling complex.

Reason: ER membrane association is the correct cellular context for CTR1's role upstream of EIN2.

Summary: CTR1 is an active Raf-like protein serine/threonine kinase.

Reason: Protein serine/threonine kinase activity is the core molecular function of CTR1.

Summary: The broader serine/threonine/tyrosine kinase annotation is less precise than the established Ser/Thr kinase activity.

Reason: CTR1 is a Raf-like Ser/Thr kinase, and the direct experimental annotation should be preferred.

Proposed replacements: protein serine/threonine kinase activity

Summary: ctr1 alleles alter bioactive gibberellin levels through ethylene pathway cross-talk, but CTR1 is not a gibberellin biosynthetic enzyme.

Reason: The paper supports CTR1/EIN3-dependent ethylene effects on GA-DELLA signaling, not a direct CTR1 role in gibberellin biosynthesis.

Summary: CTR1 negatively regulates ethylene signaling.

Reason: This directly captures CTR1's central biological role upstream of EIN2.

Summary: CTR1 negatively regulates ethylene signaling from the ER receptor complex.

Reason: This directly captures CTR1's central biological role upstream of EIN2.

Summary: The original ctr1 genetic study established CTR1 as a negative regulator of ethylene responses.

Reason: This directly captures CTR1's central biological role upstream of EIN2.

Summary: CTR1 association with ethylene receptors supports its negative regulatory position in the pathway.

Reason: This directly captures CTR1's central biological role upstream of EIN2.

Summary: Ortega-Martinez et al. (Science 2007) show that ethylene modulates quiescent-center division in the post-embryonic root stem-cell niche; the ctr1 loss-of-function mutant, with constitutive ethylene signalling, phenocopies the extra QC divisions of the ethylene-overproducing eto1 mutant.

Reason: The cached PMID:17656722 entry is abstract-only (Science; no open-access copy) and establishes the ethylene effect on QC division without naming ctr1. The CTR1-specific phenotype underlying the IMP is recorded in the reference_review of PMID:17656722 - it is reported by an independent review of this work (PMID:23183258, Lee et al. 2013 J Exp Bot, read from the publisher full text; its cache entry is also abstract-only) as "the mutant of CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1), a negative regulator of ethylene action, phenocopied the eto1 mutant". This is a downstream developmental output of CTR1's negative control of ethylene signalling, not its core kinase function.

Summary: The ctr1 loss-of-function mutant shows supernumerary quiescent-center (stem-cell niche) divisions, phenocopying eto1 (Ortega-Martinez et al. 2007), supporting a role for CTR1, via ethylene signalling, in restraining root stem-cell division.

Reason: As for GO:2000069 from the same paper - the cached abstract supports ethylene modulation of QC division, and the ctr1-specific phenotype (recorded in PMID:17656722 reference_review, corroborated by PMID:23183258) supports the IMP. Downstream developmental output of ethylene pathway control, not core function.

Summary: CTR1 affects floral transition timing through ethylene and DELLA-related pathway cross-talk.

Reason: This is a pathway output rather than CTR1's direct kinase or signaling-regulator role.

Summary: ctr1 mutants show constitutive ethylene-response phenotypes.

Reason: The response phenotype is correct, but the more informative core term is negative regulation of ethylene signaling.

Summary: CTR1/sis1 alleles affect fructose signaling through hormone cross-talk.

Reason: Fructose response is a downstream/cross-talk phenotype, not the core molecular function.

Summary: CTR1 participates in hypoxia-related ethylene signaling modulation.

Reason: Hypoxia response is a context-specific output of ethylene pathway regulation.

Summary: CTR1/sis1 alleles affect sucrose response through hormone signaling cross-talk.

Reason: Sucrose response is a downstream phenotype rather than the core CTR1 kinase function.

Summary: Sugar-hormone cross-talk review (TAS). CTR1 alleles were recovered in sugar-response screens (gin4 is a ctr1 allele; sis1 likewise), and glucose/fructose repression of CAB2 is lost in ctr1 seedlings, placing CTR1 in sugar-signalling cross-talk.

Reason: PMID:12663220 is a Trends Plant Sci review with no open-access copy (Europe PMC lists no PMC record) and an abstract-only cache entry that does not name CTR1, so the curator's statement was not seen. The function is independently supported by primary data in PMID:21253566 (ctr1/gin4 glucose-insensitivity and loss of sugar repression of CAB2). The role is a cross-talk output of CTR1's control of ethylene signalling, not its core kinase function.

Summary: Generic signal transduction under-describes the CTR1-specific ethylene pathway role.

Reason: The specific, supported process is negative regulation of ethylene-activated signaling.

Proposed replacements: negative regulation of ethylene-activated signaling pathway