ARR5

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0000156 phosphorelay response regulator activity	IMP PMID:18065689 Cytokinin regulates type-A Arabidopsis Response Regulator ac...	ACCEPT	Summary: ARR5 is a type-A response regulator whose receiver domain is phosphorylated on the conserved Asp87 via the AHK-AHP phosphorelay; this phosphorylation is required for its function and for its cytokinin-dependent stabilization. Reason: The D87A phospho-dead ARR5 fails to complement the arr3,4,5,6 mutant, directly demonstrating phosphorelay response regulator activity in planta. Supporting Evidence: PMID:18065689 Thus, phosphorylation of the receiver domain is required for ARR5 function.
GO:0000156 phosphorelay response regulator activity	ISS PMID:12068096 Two-component signal transduction pathways in Arabidopsis.	ACCEPT	Summary: ARR5 is a type-A response regulator whose receiver domain is phosphorylated on the conserved Asp87 via the AHK-AHP phosphorelay; this phosphorylation is required for its function and for its cytokinin-dependent stabilization. Reason: The D87A phospho-dead ARR5 fails to complement the arr3,4,5,6 mutant, directly demonstrating phosphorelay response regulator activity in planta. Supporting Evidence: PMID:18065689 Thus, phosphorylation of the receiver domain is required for ARR5 function. PMID:12068096 the transcriptional activation of A-type ARRs provides a negative feedback mechanism in controlling the transient induction of primary cytokinin responsive genes
GO:0000160 phosphorelay signal transduction system	IEA GO_REF:0000002	ACCEPT	Summary: ARR5 is a phospho-accepting component of the cytokinin His-Asp phosphorelay. Reason: Supported by phosphorylation-dependent function of the ARR5 receiver domain. Supporting Evidence: PMID:18065689 Cytokinin-mediated stabilization of ARR5 is disrupted in mutants of upstream phosphorelay components, suggesting that phosphorylation of type-A ARRs by two-component elements is required for protein stabilization by cytokinin.
GO:0003700 DNA-binding transcription factor activity	IBA GO_REF:0000033	REMOVE	Summary: Phylogenetic transfer of a DNA-binding transcription factor function from the response-regulator family node. Reason: ARR5 is a type-A ARR that consists essentially of a receiver domain and lacks the Myb-related GARP (B-motif) DNA-binding output domain of type-B ARRs; there is no evidence that it binds DNA. Type-A ARRs act as negative feedback regulators of the phosphorelay, not as DNA-binding transcription factors. Propagation Review Root cause: PROPAGATION BAD Failure modes: FUNCTIONAL DIVERGENCE Sources checked: PANTHER:PTN008123536 · PTN008123536 SUPPORTS SOURCE BUT NOT TARGET The node's IBD is seeded by type-B ARRs (e.g. ARR1 AT3G16857, ARR2 Q9ZWJ9), which carry a GARP/B-motif DNA-binding output domain. ARR5 is a 184-residue type-A ARR consisting of a receiver domain with a short C-terminal extension and lacks the DNA-binding output domain, so the DNA-binding transcription factor function does not transfer. Supporting Evidence: PMID:14973166 double and higher order arr mutants showed progressively increasing sensitivity to cytokinin, indicating functional overlap among type-A ARRs and that these genes act as negative regulators of cytokinin responses PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0005515 protein binding	IPI PMID:16965536 Analysis of protein interactions within the cytokinin-signal...	REMOVE	Summary: Interaction of ARR5 with the histidine phosphotransfer protein AHP4. Reason: Generic protein binding is uninformative. Interaction of type-A ARRs with AHPs is the proposed basis of their feedback inhibition and of phosphotransfer to ARR5, captured by phosphorelay response regulator activity and negative regulation of cytokinin signaling. Removal does not imply the interaction is false. Supporting Evidence: PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0005515 protein binding	IPI PMID:16965536 Analysis of protein interactions within the cytokinin-signal...	REMOVE	Summary: Interaction of ARR5 with the histidine phosphotransfer protein AHP3. Reason: Generic protein binding is uninformative. Interaction of type-A ARRs with AHPs is the proposed basis of their feedback inhibition and of phosphotransfer to ARR5, captured by phosphorelay response regulator activity and negative regulation of cytokinin signaling. Removal does not imply the interaction is false. Supporting Evidence: PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0005515 protein binding	IPI PMID:16965536 Analysis of protein interactions within the cytokinin-signal...	REMOVE	Summary: Interaction of ARR5 with the histidine phosphotransfer protein AHP1. Reason: Generic protein binding is uninformative. Interaction of type-A ARRs with AHPs is the proposed basis of their feedback inhibition and of phosphotransfer to ARR5, captured by phosphorelay response regulator activity and negative regulation of cytokinin signaling. Removal does not imply the interaction is false. Supporting Evidence: PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0005515 protein binding	IPI PMID:18642946 Toward an interaction map of the two-component signaling pat...	REMOVE	Summary: Interaction of ARR5 with the histidine phosphotransfer protein AHP3. Reason: Generic protein binding is uninformative. Interaction of type-A ARRs with AHPs is the proposed basis of their feedback inhibition and of phosphotransfer to ARR5, captured by phosphorelay response regulator activity and negative regulation of cytokinin signaling. Removal does not imply the interaction is false. Supporting Evidence: PMID:18642946 we conducted medium-scale yeast two-hybrid screens focusing on those members of the TCS, which are thought to be involved in cytokinin signaling
GO:0005634 nucleus	IBA GO_REF:0000033	ACCEPT	Summary: ARR5 is present in the nucleus. Reason: Consistent with the IDA nucleus annotation from the TCS interaction study (PMID:18642946), whose localization data are in full text not available in the cache (abstract-only); we defer to that curator. No ARR5-specific localization sentence exists in the cached publications, so the quote below documents only that the study assessed subcellular localization. Supporting Evidence: PMID:18642946 TCS proteins and their interactors localized to the same subcellular compartment in many cases, a prerequisite to being of biological relevance.
GO:0005634 nucleus	IDA PMID:18642946 Toward an interaction map of the two-component signaling pat...	ACCEPT	Summary: ARR5 is present in the nucleus. Reason: The cached abstract of PMID:18642946 (abstract-only) states only that TCS proteins and their interactors were localized; the ARR5-specific localization data are in full text not available in the cache, so we defer to the curator who read it. Nuclear presence is consistent with ARR5 interacting with nuclear-localized AHPs and type-B ARRs. Supporting Evidence: PMID:18642946 TCS proteins and their interactors localized to the same subcellular compartment in many cases, a prerequisite to being of biological relevance.
GO:0005634 nucleus	IEA GO_REF:0000120	ACCEPT	Summary: ARR5 is present in the nucleus. Reason: Consistent with the IDA nucleus annotation from the TCS interaction study (PMID:18642946), whose localization data are in full text not available in the cache (abstract-only); we defer to that curator. No ARR5-specific localization sentence exists in the cached publications, so the quote below documents only that the study assessed subcellular localization. Supporting Evidence: PMID:18642946 TCS proteins and their interactors localized to the same subcellular compartment in many cases, a prerequisite to being of biological relevance.
GO:0005737 cytoplasm	IDA PMID:18642946 Toward an interaction map of the two-component signaling pat...	ACCEPT	Summary: ARR5 is also detected in the cytoplasm. Reason: The cached abstract of PMID:18642946 (abstract-only) states only that TCS proteins and their interactors were localized; the ARR5-specific localization data are in full text not available in the cache, so we defer to the curator who read it. A cytoplasmic pool is consistent with type-A ARRs interacting with nucleo-cytosolic AHPs. Supporting Evidence: PMID:18642946 TCS proteins and their interactors localized to the same subcellular compartment in many cases, a prerequisite to being of biological relevance.
GO:0005737 cytoplasm	ISM GO_REF:0000122	ACCEPT	Summary: ARR5 is also detected in the cytoplasm. Reason: Sequence-model prediction consistent with the IDA cytoplasm annotation from PMID:18642946, whose localization data are in full text not available in the cache (abstract-only); we defer to that curator. A cytoplasmic pool is consistent with type-A ARRs interacting with nucleo-cytosolic AHPs. Supporting Evidence: PMID:18642946 TCS proteins and their interactors localized to the same subcellular compartment in many cases, a prerequisite to being of biological relevance.
GO:0006355 regulation of DNA-templated transcription	IBA GO_REF:0000033	MARK AS OVER ANNOTATED	Summary: Annotation of ARR5 to regulation of DNA-templated transcription, based on its classification as a response regulator and early descriptions of type-A ARRs as transcriptional repressors. Reason: ARR5 lacks a DNA-binding domain; it dampens cytokinin-induced transcription indirectly by negative feedback on the phosphorelay (e.g. at the level of AHPs), which is better captured by negative regulation of cytokinin-activated signaling pathway. Propagation Review Root cause: PROPAGATION BAD Failure modes: ROLE CONFLATION Sources checked: PANTHER:PTN008123536 · PTN008123536 SUPPORTS SOURCE BUT NOT TARGET Direct transcriptional regulation is appropriate for DNA-binding type-B ARR descendants but not for the receiver-only type-A ARR5, which affects transcription only indirectly through phosphorelay feedback. Supporting Evidence: PMID:11574878 The cytokinin-inducible ARR4, ARR5, ARR6 and ARR7 genes encode transcription repressors that mediate a negative feedback loop in cytokinin signalling. PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0006355 regulation of DNA-templated transcription	IEA GO_REF:0000117	MARK AS OVER ANNOTATED	Summary: Annotation of ARR5 to regulation of DNA-templated transcription, based on its classification as a response regulator and early descriptions of type-A ARRs as transcriptional repressors. Reason: ARR5 lacks a DNA-binding domain; it dampens cytokinin-induced transcription indirectly by negative feedback on the phosphorelay (e.g. at the level of AHPs), which is better captured by negative regulation of cytokinin-activated signaling pathway. Supporting Evidence: PMID:11574878 The cytokinin-inducible ARR4, ARR5, ARR6 and ARR7 genes encode transcription repressors that mediate a negative feedback loop in cytokinin signalling. PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0006355 regulation of DNA-templated transcription	TAS PMID:12068096 Two-component signal transduction pathways in Arabidopsis.	MARK AS OVER ANNOTATED	Summary: Annotation of ARR5 to regulation of DNA-templated transcription, based on its classification as a response regulator and early descriptions of type-A ARRs as transcriptional repressors. Reason: ARR5 lacks a DNA-binding domain; it dampens cytokinin-induced transcription indirectly by negative feedback on the phosphorelay (e.g. at the level of AHPs), which is better captured by negative regulation of cytokinin-activated signaling pathway. Supporting Evidence: PMID:11574878 The cytokinin-inducible ARR4, ARR5, ARR6 and ARR7 genes encode transcription repressors that mediate a negative feedback loop in cytokinin signalling. PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0007623 circadian rhythm	IMP PMID:16326927 Arabidopsis response regulators ARR3 and ARR4 play cytokinin...	MARK AS OVER ANNOTATED	Summary: Circadian period phenotype of type-A arr multiple mutants. Reason: In the cited study the long-period phenotype maps to ARR3 and ARR4; the arr5,6,8,9 quadruple mutant had a wild-type period and an ARR5 genomic transgene did not rescue the period of arr3,4,5,6. ARR5 itself therefore does not appear to contribute to circadian period control. Supporting Evidence: PMID:16326927 The arr5,6,8,9 quadruple mutant showed a wild-type period phenotype by cotyledon movement PMID:16326927 only the arr3,4 double mutant showed a striking long period
GO:0009735 response to cytokinin	IEP PMID:11115887 Characterization of the response of the Arabidopsis response...	ACCEPT	Summary: ARR5 (IBC6) is a primary cytokinin-response gene, transcriptionally induced within minutes of cytokinin application without new protein synthesis. Reason: Well-established cytokinin induction of ARR5 transcription; ARR5 expression is a standard readout of cytokinin signaling and part of the feedback loop. Supporting Evidence: PMID:11115887 A DNA fragment comprised of 1.6 kb upstream of the ARR5 transcript start site conferred cytokinin-inducible gene expression when fused to a beta-glucuronidase reporter, confirming that the transcription rate of ARR5 is elevated by cytokinin.
GO:0009735 response to cytokinin	IEP PMID:16407152 Cytokinin-mediated control of leaf longevity by AHK3 through...	ACCEPT	Summary: ARR5 (IBC6) is a primary cytokinin-response gene, transcriptionally induced within minutes of cytokinin application without new protein synthesis. Reason: Well-established cytokinin induction of ARR5 transcription; ARR5 expression is a standard readout of cytokinin signaling and part of the feedback loop. The cited abstract does not describe ARR5 expression explicitly; the annotation is retained deferring to the curator, given extensive independent evidence. Supporting Evidence: PMID:11115887 A DNA fragment comprised of 1.6 kb upstream of the ARR5 transcript start site conferred cytokinin-inducible gene expression when fused to a beta-glucuronidase reporter, confirming that the transcription rate of ARR5 is elevated by cytokinin.
GO:0009735 response to cytokinin	IEP PMID:9634588 Two genes with similarity to bacterial response regulators a...	ACCEPT	Summary: ARR5 (IBC6) is a primary cytokinin-response gene, transcriptionally induced within minutes of cytokinin application without new protein synthesis. Reason: Well-established cytokinin induction of ARR5 transcription; ARR5 expression is a standard readout of cytokinin signaling and part of the feedback loop. Supporting Evidence: PMID:9634588 The steady state level of IBC6 mRNA was elevated within 10 min by the exogenous application of cytokinin, and this induction did not require de novo protein synthesis.
GO:0009736 cytokinin-activated signaling pathway	IBA GO_REF:0000033	ACCEPT	Summary: ARR5 is a component of the cytokinin two-component pathway, acting as a cytokinin-induced negative feedback regulator. Reason: Core process; type-A ARRs act within the pathway to attenuate it. Supporting Evidence: PMID:14973166 double and higher order arr mutants showed progressively increasing sensitivity to cytokinin, indicating functional overlap among type-A ARRs and that these genes act as negative regulators of cytokinin responses PMID:12068096 the transcriptional activation of A-type ARRs provides a negative feedback mechanism in controlling the transient induction of primary cytokinin responsive genes
GO:0009736 cytokinin-activated signaling pathway	IEA GO_REF:0000120	ACCEPT	Summary: ARR5 is a component of the cytokinin two-component pathway, acting as a cytokinin-induced negative feedback regulator. Reason: Core process; type-A ARRs act within the pathway to attenuate it. Supporting Evidence: PMID:14973166 double and higher order arr mutants showed progressively increasing sensitivity to cytokinin, indicating functional overlap among type-A ARRs and that these genes act as negative regulators of cytokinin responses PMID:12068096 the transcriptional activation of A-type ARRs provides a negative feedback mechanism in controlling the transient induction of primary cytokinin responsive genes
GO:0009736 cytokinin-activated signaling pathway	IMP PMID:18065689 Cytokinin regulates type-A Arabidopsis Response Regulator ac...	ACCEPT	Summary: ARR5 is a component of the cytokinin two-component pathway, acting as a cytokinin-induced negative feedback regulator. Reason: Core process; type-A ARRs act within the pathway to attenuate it. Supporting Evidence: PMID:18065689 Thus, phosphorylation of the receiver domain is required for ARR5 function.
GO:0009736 cytokinin-activated signaling pathway	TAS PMID:12068096 Two-component signal transduction pathways in Arabidopsis.	ACCEPT	Summary: ARR5 is a component of the cytokinin two-component pathway, acting as a cytokinin-induced negative feedback regulator. Reason: Core process; type-A ARRs act within the pathway to attenuate it. Supporting Evidence: PMID:12068096 the transcriptional activation of A-type ARRs provides a negative feedback mechanism in controlling the transient induction of primary cytokinin responsive genes
GO:0010017 red or far-red light signaling pathway	IBA GO_REF:0000033	KEEP AS NON CORE	Summary: Type-A arr multiple mutants show altered red light sensitivity. Reason: Supported for the type-A ARR family (best characterized for ARR4 interacting with phytochrome B); ARR5's contribution is via higher-order mutants and is peripheral to its cytokinin feedback role. Supporting Evidence: PMID:14973166 The arr mutants show altered red light sensitivity, suggesting a general involvement of type-A ARRs in light signal transduction.
GO:0010114 response to red light	IMP PMID:14973166 Type-A Arabidopsis response regulators are partially redunda...	KEEP AS NON CORE	Summary: Type-A arr multiple mutants show altered red light sensitivity. Reason: Supported for the type-A ARR family (best characterized for ARR4 interacting with phytochrome B); ARR5's contribution is via higher-order mutants and is peripheral to its cytokinin feedback role. Supporting Evidence: PMID:14973166 The arr mutants show altered red light sensitivity, suggesting a general involvement of type-A ARRs in light signal transduction.
GO:0043565 sequence-specific DNA binding	IBA GO_REF:0000033	REMOVE	Summary: Phylogenetic transfer of a DNA-binding transcription factor function from the response-regulator family node. Reason: ARR5 is a type-A ARR that consists essentially of a receiver domain and lacks the Myb-related GARP (B-motif) DNA-binding output domain of type-B ARRs; there is no evidence that it binds DNA. Type-A ARRs act as negative feedback regulators of the phosphorelay, not as DNA-binding transcription factors. Propagation Review Root cause: PROPAGATION BAD Failure modes: FUNCTIONAL DIVERGENCE Sources checked: PANTHER:PTN008123536 · PTN008123536 SUPPORTS SOURCE BUT NOT TARGET The node's IBD is seeded by type-B ARRs (e.g. ARR1 AT3G16857, ARR2 Q9ZWJ9), which carry a GARP/B-motif DNA-binding output domain. ARR5 is a 184-residue type-A ARR consisting of a receiver domain with a short C-terminal extension and lacks the DNA-binding output domain, so the DNA-binding transcription factor function does not transfer. Supporting Evidence: PMID:14973166 double and higher order arr mutants showed progressively increasing sensitivity to cytokinin, indicating functional overlap among type-A ARRs and that these genes act as negative regulators of cytokinin responses PMID:16965536 Interaction of A-type response regulators with Arabidopsis histidine phosphotransfer proteins but not with B-type response regulators suggests that their known activity in feedback regulation may be realized by interfering at the level of Arabidopsis histidine phosphotransfer protein-mediated signaling.
GO:0080037 negative regulation of cytokinin-activated signaling pathway	IMP PMID:14973166 Type-A Arabidopsis response regulators are partially redunda...	NEW	Summary: Higher-order type-A arr mutants including arr5 are progressively hypersensitive to cytokinin, and loss of ARR5 suppresses the cytokinin resistance of axr1, showing that ARR5 negatively regulates cytokinin signaling. Reason: The negative-feedback role is the defining biological function of ARR5 but is not captured in GOA, which only lists the pathway itself; the specific regulatory term is warranted by genetic evidence. Supporting Evidence: PMID:14973166 double and higher order arr mutants showed progressively increasing sensitivity to cytokinin, indicating functional overlap among type-A ARRs and that these genes act as negative regulators of cytokinin responses PMID:23279608 the cytokinin resistance of axr1 seedlings is suppressed by loss of function of the type A ARR family member ARR5 PMID:18065689 Thus, phosphorylation of the receiver domain is required for ARR5 function.

Gene Description

Existing Annotations Review

Core Functions

ARR5 is a cytokinin-induced type-A response regulator whose receiver domain accepts phosphoryl groups from the AHP phosphorelay; phosphorylated ARR5 is stabilized and acts as a negative feedback regulator that attenuates cytokinin signaling.

References

Suggested Questions for Experts

Suggested Experiments

📚 Additional Documentation

Notes

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