ABI1

Existing Annotations Review

GO Term	Evidence	Action	Reason
GO:0006470 protein dephosphorylation	TAS PMID:9869399 Protein phosphatase 2C (PP2C) function in higher plants.	ACCEPT	Summary: ABI1/ABI2 are central PP2Cs in ABA signaling. Reason: ABI1/ABI2 are central PP2Cs in ABA signaling. protein dephosphorylation is a core molecular/process annotation for ABI1 phosphatase function. Supporting Evidence: PMID:9869399 the ABI1/ABI2 PP2Cs are central components in abscisic acid (ABA) signal transduction.
GO:0009408 response to heat	IMP PMID:15923322 Heat stress phenotypes of Arabidopsis mutants implicate mult...	KEEP AS NON CORE	Summary: abi1 has impaired acquired thermotolerance. Reason: abi1 has impaired acquired thermotolerance. This is a supported physiological output, but the core role is PP2C-mediated negative regulation of ABA signaling. Supporting Evidence: PMID:15923322 Abscisic acid (ABA) signaling mutants (abi1 and abi2) and the UV-sensitive mutant, uvh6, showed the strongest defects in acquired thermotolerance of root growth and seedling survival.
GO:0009409 response to cold	IMP PMID:12228349 Role of Abscisic Acid in Drought-Induced Freezing Tolerance,...	KEEP AS NON CORE	Summary: The abi1 and aba-1 mutants have impaired induced freezing tolerance in this study. Reason: The abi1 and aba-1 mutants have impaired induced freezing tolerance in this study. This is a supported physiological output, but the core role is PP2C-mediated negative regulation of ABA signaling. Supporting Evidence: PMID:12228349 ABA appears to be involved in both LT- and drought-induced freezing tolerance, since both ABA mutants were impaired in their responses to these stimuli.
GO:0009409 response to cold	IMP PMID:1834244 Cold acclimation and cold-regulated gene expression in ABA m...	UNDECIDED	Summary: The 1991 cor-expression assays do not resolve a cold-response role for ABI1 relative to the later freezing study. Reason: The 1991 abstract reports normal cold-regulated cor expression and no apparent freezing-tolerance effect of abi mutations. This differs from the 1995 study; full experimental context is needed before adjudicating this specific annotation. Supporting Evidence: PMID:1834244 Cold-regulated expression of all three cor genes, however, was nearly the same in wild-type and abi1 mutant plants.
GO:0009737 response to abscisic acid	IMP PMID:8492808 Abscisic acid-insensitive mutations provide evidence for sta...	KEEP AS NON CORE	Summary: ABI1 affects ABA inducibility in a developmental-stage-dependent manner. Reason: ABI1 affects ABA inducibility in a developmental-stage-dependent manner. This is a supported physiological output, but the core role is PP2C-mediated negative regulation of ABA signaling. Supporting Evidence: PMID:8492808 the abi1 and abi2 mutants showed a very slight reduction of ABA inducibility in 8-day-old plants
GO:0009787 regulation of abscisic acid-activated signaling pathway	IMP PMID:18298671 Nuclear localization of the mutant protein phosphatase abi1 ...	MODIFY	Summary: Nuclear ABI1 accumulation is associated with enhanced inhibition of ABA responses. Reason: Nuclear ABI1 accumulation is associated with enhanced inhibition of ABA responses. The evidence supports the more specific negative-regulation term for ABI1's PP2C role in ABA signaling. Proposed replacements: negative regulation of abscisic acid-activated signaling pathway Supporting Evidence: PMID:18298671 Application of a proteosomal inhibitor led to both a preferential nuclear accumulation of ABI1 and an enhancement of PP2C-dependent inhibitory action on the ABA response. PMID:19407143 RCAR1 was shown to bind ABA, to mediate ABA-dependent inactivation of ABI1 or ABI2 in vitro, and to antagonize PP2C action in planta.
GO:0009788 negative regulation of abscisic acid-activated signaling pathway	IMP PMID:16614222 A bifurcating pathway directs abscisic acid effects on stoma...	ACCEPT	Summary: PA binding to ABI1 links ABA signaling to stomatal closure. Reason: PA binding to ABI1 links ABA signaling to stomatal closure. Regulation, especially negative regulation, of ABA signaling is the central biological process for ABI1. Supporting Evidence: PMID:16614222 PLDalpha1-produced phosphatidic acid (PA) binds to the ABI1 PP2C to signal ABA-promoted stomatal closure PMID:19407143 RCAR1 was shown to bind ABA, to mediate ABA-dependent inactivation of ABI1 or ABI2 in vitro, and to antagonize PP2C action in planta.
GO:0010119 regulation of stomatal movement	IMP PMID:16614222 A bifurcating pathway directs abscisic acid effects on stoma...	KEEP AS NON CORE	Summary: PA binding to ABI1 links ABA signaling to stomatal closure. Reason: PA binding to ABI1 links ABA signaling to stomatal closure. This is a supported physiological output, but the core role is PP2C-mediated negative regulation of ABA signaling. Supporting Evidence: PMID:16614222 PLDalpha1-produced phosphatidic acid (PA) binds to the ABI1 PP2C to signal ABA-promoted stomatal closure
GO:0004721 phosphoprotein phosphatase activity	IDA PMID:22090030 Molecular mechanism for inhibition of a critical component i...	MODIFY	Summary: ABI1 recognizes the SnRK2.6 activation loop for dephosphorylation. Reason: ABI1 recognizes the SnRK2.6 activation loop for dephosphorylation. The PP2C family and experimental ABI1 studies support the more specific Ser/Thr protein phosphatase term. Proposed replacements: protein serine/threonine phosphatase activity Supporting Evidence: PMID:22090030 Structural modeling suggested that the two interfaces lock SnRK2.6 and ABI1 in an orientation such that the activation loop of SnRK2.6 is posited to the catalytic site of ABI1 for dephosphorylation. PMID:8898906 recombinant proteins that contained the ABI1 C-terminal domain displayed in vitro phosphatase activity towards 32P-labelled casein, and this activity displayed Mg2+ or Mn2+ dependence and okadaic acid insensitivity typical of protein phosphatases 2C.
GO:0004722 protein serine/threonine phosphatase activity	IEA GO_REF:0000002	ACCEPT	Summary: ABI1 is a PP2C protein serine/threonine phosphatase that dephosphorylates ABA signaling substrates. Reason: This electronic catalytic-function mapping agrees with direct ABI1 PP2C assays in PMID:8898906 and PMID:9537523; the precise Ser/Thr phosphatase function is supported independently of the mapping.
GO:0004722 protein serine/threonine phosphatase activity	IEA GO_REF:0000003	ACCEPT	Summary: ABI1 is a PP2C protein serine/threonine phosphatase that dephosphorylates ABA signaling substrates. Reason: This electronic catalytic-function mapping agrees with direct ABI1 PP2C assays in PMID:8898906 and PMID:9537523; the precise Ser/Thr phosphatase function is supported independently of the mapping.
GO:0004722 protein serine/threonine phosphatase activity	IEA GO_REF:0000116	ACCEPT	Summary: ABI1 is a PP2C protein serine/threonine phosphatase that dephosphorylates ABA signaling substrates. Reason: This electronic catalytic-function mapping agrees with direct ABI1 PP2C assays in PMID:8898906 and PMID:9537523; the precise Ser/Thr phosphatase function is supported independently of the mapping.
GO:0004722 protein serine/threonine phosphatase activity	IEA GO_REF:0000117	ACCEPT	Summary: ABI1 is a PP2C protein serine/threonine phosphatase that dephosphorylates ABA signaling substrates. Reason: This electronic catalytic-function mapping agrees with direct ABI1 PP2C assays in PMID:8898906 and PMID:9537523; the precise Ser/Thr phosphatase function is supported independently of the mapping.
GO:0004722 protein serine/threonine phosphatase activity	EXP PMID:10645425 The role of ABI1 in abscisic acid signal transduction: from ...	ACCEPT	Summary: Biochemistry and complementation establish PP2C activity. Reason: Biochemistry and complementation establish PP2C activity. protein serine/threonine phosphatase activity is a core molecular/process annotation for ABI1 phosphatase function. Supporting Evidence: PMID:10645425 A combination of in vitro assays and yeast mutant complementation studies confirmed that ABI1 is a functional protein phosphatase 2C.
GO:0004722 protein serine/threonine phosphatase activity	IDA PMID:8898906 Protein phosphatase activity of abscisic acid insensitive 1 ...	ACCEPT	Summary: ABI1 has Mg/Mn-dependent PP2C catalytic activity. Reason: ABI1 has Mg/Mn-dependent PP2C catalytic activity. protein serine/threonine phosphatase activity is a core molecular/process annotation for ABI1 phosphatase function. Supporting Evidence: PMID:8898906 recombinant proteins that contained the ABI1 C-terminal domain displayed in vitro phosphatase activity towards 32P-labelled casein, and this activity displayed Mg2+ or Mn2+ dependence and okadaic acid insensitivity typical of protein phosphatases 2C.
GO:0004722 protein serine/threonine phosphatase activity	IDA PMID:9537523 ABI1 of Arabidopsis is a protein serine/threonine phosphatas...	ACCEPT	Summary: ABI1 is a magnesium-sensitive protein serine/threonine phosphatase. Reason: ABI1 is a magnesium-sensitive protein serine/threonine phosphatase. protein serine/threonine phosphatase activity is a core molecular/process annotation for ABI1 phosphatase function. Supporting Evidence: PMID:9537523 The ABI1 protein (ABI1p) has been characterized as a protein serine/threonine phosphatase of type 2C that is highly affected in its activity by changes in the proton and magnesium ion concentrations.
GO:0005509 calcium ion binding	TAS PMID:7910981 Arabidopsis ABA response gene ABI1: features of a calcium-mo...	MARK AS OVER ANNOTATED	Summary: An early sequence analysis proposed an EF-hand calcium-binding site; this was not a direct calcium-binding assay. Reason: The original paper proposes a calcium-binding motif from sequence, while PMID:8898906 reports that the putative EF-hand is unlikely to mediate phosphatase regulation at physiological calcium concentrations. Retain MARK_AS_OVER_ANNOTATED for an unestablished calcium-binding activity; this is not justified merely by the greater informativeness of phosphatase activity. Supporting Evidence: PMID:7910981 the ABI1 protein has a unique amino-terminal extension containing an EF hand calcium-binding site. PMID:8898906 the putative EF-hand motif is unlikely to mediate Ca2+ regulation of the ABI1 phosphatase activity at physiological Ca2+ concentrations
GO:0005509 calcium ion binding	TAS PMID:8197457 A protein phosphatase 2C involved in ABA signal transduction...	MARK AS OVER ANNOTATED	Summary: The original cloning paper proposed a putative calcium-binding site from sequence. Reason: The original paper proposes a calcium-binding motif from sequence, while PMID:8898906 reports that the putative EF-hand is unlikely to mediate phosphatase regulation at physiological calcium concentrations. Retain MARK_AS_OVER_ANNOTATED for an unestablished calcium-binding activity; this is not justified merely by the greater informativeness of phosphatase activity. Supporting Evidence: PMID:8197457 The ABI1 gene encodes a protein with high similarity to protein serine or threonine phosphatases of type 2C with the novel feature of a putative Ca2+ binding site. PMID:8898906 the putative EF-hand motif is unlikely to mediate Ca2+ regulation of the ABI1 phosphatase activity at physiological Ca2+ concentrations
GO:0005515 protein binding	IPI PMID:16365038 The regulatory domain of SRK2E/OST1/SnRK2.6 interacts with A...	REMOVE	Summary: ABI1 physically interacts with the ABA-responsive regulatory domain of OST1/SnRK2.6. Reason: ABI1 physically interacts with the ABA-responsive regulatory domain of OST1/SnRK2.6. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:16365038 Domain II interacted with the ABI1 protein in a yeast two-hybrid assay.
GO:0005515 protein binding	IPI PMID:17267444 The role of Arabidopsis SCAR genes in ARP2-ARP3-dependent ce...	UNDECIDED	Summary: The SCAR/WAVE study does not expose the identity of the ABI protein in the accessible interaction experiment. Reason: The cached abstract describes Arabidopsis SCAR/WAVE interaction experiments but does not establish which ABI protein was assayed. A full-text search did not resolve the construct identity. The previous claim of ABI name confusion and removal was not justified by the accessible evidence.
GO:0005515 protein binding	IPI PMID:19407142 Abscisic acid inhibits type 2C protein phosphatases via the ...	REMOVE	Summary: ABA-regulated PYR1-PP2C interaction was confirmed in plants. Reason: ABA-regulated PYR1-PP2C interaction was confirmed in plants. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:19407142 Co-immunoprecipitation experiments performed on ABA or mock-treated plants recapitulate the PYR1-PP2C interactions observed in yeast
GO:0005515 protein binding	IPI PMID:19407143 Regulators of PP2C phosphatase activity function as abscisic...	REMOVE	Summary: ABA receptor RCAR1 inhibits ABI1 and ABI2. Reason: ABA receptor RCAR1 inhibits ABI1 and ABI2. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:19407143 RCAR1 was shown to bind ABA, to mediate ABA-dependent inactivation of ABI1 or ABI2 in vitro, and to antagonize PP2C action in planta.
GO:0005515 protein binding	IPI PMID:19769575 Closely related receptor complexes differ in their ABA selec...	REMOVE	Summary: RCAR3 physically interacts with ABI1/ABI2. Reason: RCAR3 physically interacts with ABI1/ABI2. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:19769575 RCAR3 was identified in a screen for interactors of the PP2Cs ABI1 and ABI2
GO:0005515 protein binding	IPI PMID:19805022 Type 2C protein phosphatases directly regulate abscisic acid...	MODIFY	Summary: Group A PP2Cs inhibit SnRK2 kinases by activation-loop dephosphorylation. Reason: The cited functional experiments establish that ABI1 dephosphorylates and inactivates SnRK2 protein kinases. Replace generic protein binding with the demonstrated serine/threonine phosphatase activity, rather than treating substrate association as a separate uninformative function. Proposed replacements: protein serine/threonine phosphatase activity Supporting Evidence: PMID:19805022 Group A PP2Cs interacted physically with SnRK2s in various combinations, and efficiently inactivated ABA-activated SnRK2s via dephosphorylation of multiple Ser/Thr residues in the activation loop.
GO:0005515 protein binding	IPI PMID:19855379 Structural basis of abscisic acid signalling.	REMOVE	Summary: The ABA-PYL1-ABI1 complex structurally explains phosphatase inhibition. Reason: The ABA-PYL1-ABI1 complex structurally explains phosphatase inhibition. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:19855379 (+)-ABA-bound PYL1 tightly interacts with a PP2C domain of ABI1 by using the hydrophobic pocket to cover the active site of ABI1 like a plug.
GO:0005515 protein binding	IPI PMID:19874541 PYR/PYL/RCAR family members are major in-vivo ABI1 protein p...	REMOVE	Summary: ABI1 associates with three ABA-responsive SnRK2 kinases in planta. Reason: ABI1 associates with three ABA-responsive SnRK2 kinases in planta. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:19874541 We confirm previous studies in yeast and now show that ABI1 interacts with the ABA-signalling kinases OST1, SnRK2.2 and SnRK2.3 in plants.
GO:0005515 protein binding	IPI PMID:19893533 Structural insights into the mechanism of abscisic acid sign...	REMOVE	Summary: ABA-bound PYL1 occludes the ABI1 active site. Reason: ABA-bound PYL1 occludes the ABI1 active site. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:19893533 In the ternary complex, the CL2 loop is located near the active site of ABI1, blocking the entry of substrate proteins.
GO:0005515 protein binding	IPI PMID:19898420 A gate-latch-lock mechanism for hormone signalling by abscis...	REMOVE	Summary: PYR1 and PYL1-6 were tested for interaction with ABI1 as well as other PP2Cs. Reason: PYR1 and PYL1-6 were tested for interaction with ABI1 as well as other PP2Cs. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:19898420 Each of these family members was capable of interacting with the ABA-signaling PP2Cs HAB1, ABI1, and ABI2
GO:0005515 protein binding	IPI PMID:19924127 In vitro reconstitution of an abscisic acid signalling pathw...	MODIFY	Summary: Reconstitution establishes direct phosphatase control of SnRK2 activity. Reason: The cited functional experiments establish that ABI1 dephosphorylates and inactivates SnRK2 protein kinases. Replace generic protein binding with the demonstrated serine/threonine phosphatase activity, rather than treating substrate association as a separate uninformative function. Proposed replacements: protein serine/threonine phosphatase activity Supporting Evidence: PMID:19924127 the SnRK2 kinases are kept inactive by the PP2Cs through physical interaction and dephosphorylation.
GO:0005515 protein binding	IPI PMID:19955405 Activity of guard cell anion channel SLAC1 is controlled by ...	UNDECIDED	Summary: The PP2CA-focused abstract does not identify the ABI1 interaction assay underlying this row. Reason: The abstract emphasizes PP2CA and does not expose the ABI1-specific interaction experiment. ABI1-OST1 interaction is established independently, but this reference-specific row remains unresolved.
GO:0005515 protein binding	IPI PMID:19955427 A protein kinase-phosphatase pair interacts with an ion chan...	UNDECIDED	Summary: The PP2CA-OST1-SLAC1 abstract does not expose the ABI1-specific interaction experiment. Reason: The accessible abstract reports PP2CA interactions with OST1 and SLAC1. It does not identify the ABI1 assay underlying this source row; the full experiment is needed to adjudicate it. No wrong-gene inference or rejection of an ABI1 interaction follows from an abstract focused on PP2CA.
GO:0005515 protein binding	IPI PMID:20729862 Identification and mechanism of ABA receptor antagonism.	REMOVE	Summary: The PYL1-pyrabactin-ABI1 complex supports receptor interaction. Reason: The PYL1-pyrabactin-ABI1 complex supports receptor interaction. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:20729862 Crystal structures of the PYL2-pyrabactin and PYL1-pyrabactin-ABI1 complexes reveal the mechanism responsible for receptor-selective activation and inhibition
GO:0005515 protein binding	IPI PMID:21436041 Jasmonate signaling involves the abscisic acid receptor PYL4...	UNDECIDED	Summary: The PYL-dependent metabolic-regulation abstract does not expose an ABI1-specific interaction assay. Reason: The cached abstract establishes PYL-dependent metabolic regulation but does not expose the ABI1 interaction assay. Do not infer an incorrect annotation from its tobacco focus.
GO:0005515 protein binding	IPI PMID:21658606 The molecular basis of ABA-independent inhibition of PP2Cs b...	UNDECIDED	Summary: The PYL10-HAB1 abstract does not resolve the separate ABI1 interaction assertion. Reason: The abstract emphasizes PYL10-HAB1 and does not expose the ABI1-specific assay. Related PP2C results cannot verify this precise interaction row.
GO:0005515 protein binding	IPI PMID:21798944 Evidence for network evolution in an Arabidopsis interactome...	UNDECIDED	Summary: The Arabidopsis interactome abstract does not identify the ABI1 partner recorded in the source interaction table. Reason: This is a large Arabidopsis interactome study; the abstract does not identify the ABI1 interaction pair. The source interaction table remains to be checked.
GO:0005515 protein binding	IPI PMID:24165892 Molecular basis for the selective and ABA-independent inhibi...	UNDECIDED	Summary: The extracted PYL13-PP2CA results do not expose the ABI1-specific interaction evidence. Reason: The accessible extracted text discusses PYL13-PP2CA selectivity without an ABI1-specific assay. The cached full-text flag does not guarantee the extraction includes all results or supplements.
GO:0005515 protein binding	IPI PMID:26443375 Arabidopsis ABA-Activated Kinase MAPKKK18 is Regulated by Pr...	MODIFY	Summary: ABI1 interacts with and inhibits MKKK18. Reason: The cited work directly identifies ABI1 as a MKKK18-interacting protein and demonstrates inhibition of kinase activity. Protein kinase inhibitor activity captures this measured regulatory function more informatively than generic binding; this assignment does not require inferring a phosphatase-independent inhibition mechanism. Proposed replacements: protein kinase inhibitor activity Supporting Evidence: PMID:26443375 Notably, we identified abscisic acid insensitive 1 (ABI1) PP2C as a MKKK18-interacting protein, and demonstrated that ABI1 inhibited its activity.
GO:0005515 protein binding	IPI PMID:27192441 Release of GTP Exchange Factor Mediated Down-Regulation of A...	REMOVE	Summary: ABI1 directly interacts with RopGEF1. Reason: ABI1 directly interacts with RopGEF1. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:27192441 RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1.
GO:0005515 protein binding	IPI PMID:27923613 Arabidopsis thaliana RECEPTOR DEAD KINASE1 Functions as a Po...	REMOVE	Summary: RDK1 recruits ABI1 to the plasma membrane. Reason: RDK1 recruits ABI1 to the plasma membrane. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:27923613 RDK1 interacted in the plasma membrane with type 2C protein phosphatase ABSCISIC ACID INSENSITIVE1 (ABI1)
GO:0005515 protein binding	IPI PMID:29928509 CARK1 mediates ABA signaling by phosphorylation of ABA recep...	REMOVE	Summary: RCAR3 phosphorylation strengthens binding to ABI1. Reason: RCAR3 phosphorylation strengthens binding to ABI1. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:29928509 Surface plasmon resonance (SPR) assay further demonstrated the phosphorylation of RCAR3 by CARK1 could distinctly enhance its interaction with ABI1 in vitro.
GO:0005515 protein binding	IPI PMID:32490347 A point-to-point protein-protein interaction assay reveals t...	REMOVE	Summary: JAZ1-ABI1 interaction contributes to hormone signaling cross-talk. Reason: JAZ1-ABI1 interaction contributes to hormone signaling cross-talk. Remove the uninformative generic protein-binding annotation while retaining this interaction evidence. This does not reject the interaction, and interaction alone does not establish a distinct molecular activity beyond the supported functions reviewed elsewhere. Supporting Evidence: PMID:32490347 we next revealed the signaling cross talk between jasmonate and abscisic acid by characterizing the JAZ1-PYL4 and JAZ1-ABI1 interactions.
GO:0005515 protein binding	IPI PMID:32612234 Extensive signal integration by the phytohormone protein net...	UNDECIDED	Summary: The hormone-network abstract does not enumerate the ABI1 interaction pair. Reason: The hormone-network abstract does not enumerate the ABI1-specific pair. The source interaction table remains to be checked.
GO:0016791 phosphatase activity	IDA PMID:24179127 ABI1 and PP2CA phosphatases are negative regulators of Snf1-...	MODIFY	Summary: ABI1 and PP2CA couple ABA and energy signaling by inhibiting SnRK1. Reason: The recovered full text demonstrates ABI1-dependent SnRK1.1 dephosphorylation, corroborating the specific protein serine/threonine phosphatase term together with established PP2C enzymology. Proposed replacements: protein serine/threonine phosphatase activity Supporting Evidence: PMID:24179127 two clade A type 2C protein phosphatases (PP2Cs), established repressors of the abscisic acid (ABA) hormonal pathway, interact with the SnRK1 catalytic subunit causing its dephosphorylation and inactivation. PMID:8898906 recombinant proteins that contained the ABI1 C-terminal domain displayed in vitro phosphatase activity towards 32P-labelled casein, and this activity displayed Mg2+ or Mn2+ dependence and okadaic acid insensitivity typical of protein phosphatases 2C.
GO:0019900 kinase binding	IPI PMID:24179127 ABI1 and PP2CA phosphatases are negative regulators of Snf1-...	MODIFY	Summary: ABI1 and PP2CA couple ABA and energy signaling by inhibiting SnRK1. Reason: The recovered full text shows ABI1-SnRK1.1 interaction by yeast two-hybrid and co-immunoprecipitation. SnRK1 is a Ser/Thr kinase, supporting refinement to protein serine/threonine kinase binding. Proposed replacements: protein serine/threonine kinase binding Supporting Evidence: PMID:24179127 SnRK1.1 interacted with ABI1 and PP2CA in yeast cells, and deletion of its regulatory domain (RD) abolished this interaction
GO:0019901 protein kinase binding	IPI PMID:20385816 Guard cell anion channel SLAC1 is regulated by CDPK protein ...	UNDECIDED	Summary: ABI1 suppresses CPK-dependent channel activation, but direct ABI1-kinase binding remains unverified. Reason: The abstract establishes ABI1 suppression of CPK-dependent channel activation, but does not show the direct ABI1-kinase binding assay needed to justify the proposed narrower binding term. Supporting Evidence: PMID:20385816 In line with activation by OST1, CPK activation of the guard cell anion channel was suppressed by ABI1.
GO:0043169 cation binding	IEA GO_REF:0000002	KEEP AS NON CORE	Summary: Divalent-cation dependence is consistent with ABI1 catalysis. Reason: The InterPro cation-binding inference is biologically consistent with the Mg2+/Mn2+ requirement demonstrated in PMID:8898906. A broad metal-binding term adds little beyond PP2C catalysis but is not an over-annotation solely because it is broad.
GO:0009737 response to abscisic acid	IEP PMID:25680457 An abscisic acid inducible Arabidopsis MAPKKK, MAPKKK18 regu...	UNDECIDED	Summary: ABA induction of MAPKKK18 does not establish the ABI1 expression response asserted by this IEP row. Reason: The abstract reports ABA induction of MAPKKK18, but does not show the ABI1 expression measurement underlying this IEP annotation. The original figure or supplement is required.
GO:0009788 negative regulation of abscisic acid-activated signaling pathway	IGI PMID:18835996 F-box protein DOR functions as a novel inhibitory factor for...	ACCEPT	Summary: Genetic epistasis places abi1-1 downstream of DOR in the ABA response. Reason: Genetic epistasis places abi1-1 downstream of DOR in the ABA response. Regulation, especially negative regulation, of ABA signaling is the central biological process for ABI1. Supporting Evidence: PMID:18835996 Double-mutant analyses of dor with ABA-insensitive mutant abi1-1 showed that abi1-1 is epistatic to dor PMID:19407143 RCAR1 was shown to bind ABA, to mediate ABA-dependent inactivation of ABI1 or ABI2 in vitro, and to antagonize PP2C action in planta.
GO:0009788 negative regulation of abscisic acid-activated signaling pathway	IMP PMID:26443375 Arabidopsis ABA-Activated Kinase MAPKKK18 is Regulated by Pr...	ACCEPT	Summary: ABI1 interacts with and inhibits MKKK18. Reason: ABI1 interacts with and inhibits MKKK18. Regulation, especially negative regulation, of ABA signaling is the central biological process for ABI1. Supporting Evidence: PMID:26443375 Notably, we identified abscisic acid insensitive 1 (ABI1) PP2C as a MKKK18-interacting protein, and demonstrated that ABI1 inhibited its activity.
GO:1902531 regulation of intracellular signal transduction	IBA GO_REF:0000033	ACCEPT	Summary: Inherited intracellular signaling regulation is consistent with ABI1 phosphatase function. Reason: The PAINT IBA asserts inherited participation in intracellular signaling regulation, consistent with ABI1 PP2C function. The target-specific ABA mechanism provides additional specificity but does not invalidate the broader ancestral inference.
GO:0005634 nucleus	IEA GO_REF:0000044	ACCEPT	Summary: ABI1 has documented nucleus localization compatible with ABA signaling outputs. Reason: Nuclear and cytoplasmic localization are compatible with ABI1 regulation of SnRK2s and ABA-responsive transcription.
GO:0005634 nucleus	IDA PMID:18298671 Nuclear localization of the mutant protein phosphatase abi1 ...	ACCEPT	Summary: Nuclear ABI1 accumulation is associated with enhanced inhibition of ABA responses. Reason: Nuclear ABI1 accumulation is associated with enhanced inhibition of ABA responses. Nuclear and cytoplasmic localization are compatible with ABI1 regulation of SnRK2s and ABA-responsive transcription. Supporting Evidence: PMID:18298671 Application of a proteosomal inhibitor led to both a preferential nuclear accumulation of ABI1 and an enhancement of PP2C-dependent inhibitory action on the ABA response.
GO:0005737 cytoplasm	IEA GO_REF:0000044	ACCEPT	Summary: ABI1 has documented cytoplasm localization compatible with ABA signaling outputs. Reason: Nuclear and cytoplasmic localization are compatible with ABI1 regulation of SnRK2s and ABA-responsive transcription.
GO:0005737 cytoplasm	ISM GO_REF:0000122	ACCEPT	Summary: ABI1 has documented cytoplasm localization compatible with ABA signaling outputs. Reason: Nuclear and cytoplasmic localization are compatible with ABI1 regulation of SnRK2s and ABA-responsive transcription.
GO:0005886 plasma membrane	IEA GO_REF:0000044	KEEP AS NON CORE	Summary: ABI1 can be recruited to the plasma membrane by RDK1. Reason: PMID:27923613 reports RDK1-ABI1 interaction at the plasma membrane, supporting the electronic location mapping. This is a context-dependent site in addition to nucleocytoplasmic action.
GO:0008287 protein serine/threonine phosphatase complex	TAS PMID:9869399 Protein phosphatase 2C (PP2C) function in higher plants.	UNDECIDED	Summary: The PP2C review supports ABI1 signaling activity but does not establish membership in a defined phosphatase complex. Reason: The abstract describes PP2C enzymes in signaling but does not establish a defined protein serine/threonine phosphatase complex containing ABI1. Catalytic activity alone does not establish complex membership. Supporting Evidence: PMID:9869399 the ABI1/ABI2 PP2Cs are central components in abscisic acid (ABA) signal transduction.

Gene Description

Existing Annotations Review

Core Functions

Clade A PP2C protein serine/threonine phosphatase activity that negatively regulates abscisic acid signaling by dephosphorylating and inhibiting ABA-activated SnRK kinases until ABA-bound PYR/PYL/RCAR receptors inhibit ABI1.

References

Suggested Questions for Experts

Suggested Experiments

Deep Research

Falcon

📚 Additional Documentation

Notes

📄 View Raw YAML