ABCB1/PGP1 is an ATP-binding cassette transporter that exports auxin and bioactive brassinosteroids across the Arabidopsis plasma membrane. It contributes to tissue auxin movement and shares developmental functions with ABCB19, including cell elongation, light-dependent growth and stamen and pollen development. TWD1 regulates its membrane localization and auxin transport activity. Purified ABCB1 directly transports brassinolide in proteoliposomes, and structural studies resolve hormone and nucleotide binding. Auxin export is supported by native and heterologous cell assays, including TWD1 coexpression, but was not detected in the same purified proteoliposome system; the molecular basis of this assay dependence remains incompletely resolved.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005515 protein binding | IPI PMID:14517332 TWISTED DWARF1, a unique plasma membrane-anchored immunophil... | REMOVE | Summary: ABCB1 physically and functionally interacts with TWD1, but bare protein binding adds no functional specificity. Reason: Retain the measured interaction and transporter activation as evidence for the export mechanism. This row does not establish that ABCB1 itself regulates another transporter or catalyzes chaperoning. Remove uninformative GO:0005515 under the binding policy without denying the TWD1 interaction. Supporting Evidence: PMID:32699109 The D/E-P1008 motif is also important for ABCB1-TWD1 interactions and activation of ABCB1-mediated auxin transport by TWD1. |
| GO:0005524 ATP binding | IEA GO_REF:0000002 | ACCEPT | Summary: ATP binding is an integral property of the ABCB1 transport cycle. Reason: The nucleotide-bound cryo-EM structure, conserved NBDs and ATP-dependent transport establish this core binding property. The trapped EQ mutant structure resolves binding; ATP hydrolysis and transport require separate wild-type assays. Supporting Evidence: PMID:39497419 the ATP plus BL-bound structure of ABCB1 |
| GO:0005634 nucleus | ISM GO_REF:0000122 | MARK AS OVER ANNOTATED | Summary: The AtSubP nuclear assignment overextends sequence prediction for the intact ABCB1 membrane transporter. Reason: AtSubP is an ISM compartment prediction; experimental-curator deference does not apply. Native PGP1/ABCB1 imaging supports a plasma-membrane pool; its experimentally curated multipass topology and the ABCB1 structure in PMID:39497419 establish an integral membrane transporter, not a soluble nuclear protein. Assigning the intact carrier to the nucleus from the sequence classifier alone exceeds the target-specific localization evidence and does not account for the established membrane architecture and trafficking. MARK_AS_OVER_ANNOTATED reflects that unsupported compartment assignment, not a demonstrated absence from every nuclear-envelope pool. A hypothetical nuclear membrane pool or cleaved fragment is not positive support for this row; no such target-specific mechanism is established by the cited studies. Supporting Evidence: PMID:17237354 PGP1 and PGP19 colocalized with PIN1 in the shoot apex in Arabidopsis thaliana and with PIN1 and PIN2 in root tissues file:ARATH/ABCB1/ABCB1-uniprot.txt Multi-pass membrane protein {ECO:0000255, ECO:0000269|PubMed:14517332, ECO:0000269|PubMed:16212599, ECO:0000269|PubMed:9761790}. |
| GO:0005783 endoplasmic reticulum | HDA PMID:28887381 Global Analysis of Membrane-associated Protein Oligomerizati... | ACCEPT | Summary: ABCB1 can reside in the ER during defective TWD1-dependent trafficking. Reason: The 2017 HDA supplements place ABCB1 in sucrose-gradient/raw-peptide data but do not independently resolve an ER assignment. Separate direct native-promoter fusion imaging in PMID20971896 documents ABCB1 ER retention in twd1. Retain the informative root-organelle claim with this perturbation context; this does not make the ER the established site of normal hormone export or claim the HDA study directly showed ER residence. Supporting Evidence: PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane file:ARATH/ABCB19/ABCB19-bioinformatics/README.md ABCB1 AT2G36910.1 was found in S4 sucrose-gradient/raw-peptide data, but not in the S1 `Mapp` summary; this inspection did not verify an ER-specific assignment. |
| GO:0005886 plasma membrane | EXP PMID:14517332 TWISTED DWARF1, a unique plasma membrane-anchored immunophil... | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0005886 plasma membrane | EXP PMID:16212599 Cellular efflux of auxin catalyzed by the Arabidopsis MDR/PG... | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0005886 plasma membrane | HDA PMID:14506206 Large-scale analysis of in vivo phosphorylated membrane prot... | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0005886 plasma membrane | HDA PMID:16618929 Mapping the Arabidopsis organelle proteome. | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0005886 plasma membrane | HDA PMID:22923678 Putative glycosyltransferases and other plant Golgi apparatu... | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0005886 plasma membrane | IDA PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0005886 plasma membrane | IDA PMID:9761790 Involvement of an ABC transporter in a developmental pathway... | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0005886 plasma membrane | IEA GO_REF:0000120 | ACCEPT | Summary: ABCB1 is a plasma-membrane hormone transporter. Reason: Independent targeted localization in native tissues, membrane-proteomic observations and functional export assays consistently support this location. PMID35512423 specifically images ABCB1βGFP in anther endothecium and middle-layer cells; ER retention when TWD1 is absent is a separate trafficking state, not a reason to reject normal PM residence. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane PMID:20971896 Mutations in TWD1 caused mislocalization of ABCB1, ABCB4, and ABCB19 to the ER instead of the plasma membrane |
| GO:0008361 regulation of cell size | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1 contributes to cell-size regulation through hormone transport. Reason: Light-dependent hypocotyl growth provides physiological context, and the later stamen study directly measures shorter/wider epidermal cells in the abcb1abcb19 double mutant. This establishes a shared transport-dependent size-control role without claiming ABCB1 alone determines all cell dimensions. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced |
| GO:0008361 regulation of cell size | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: ABCB1 contributes to cell-size regulation through hormone transport. Reason: Light-dependent hypocotyl growth provides physiological context, and the later stamen study directly measures shorter/wider epidermal cells in the abcb1abcb19 double mutant. This establishes a shared transport-dependent size-control role without claiming ABCB1 alone determines all cell dimensions. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced |
| GO:0009506 plasmodesma | HDA PMID:21533090 Arabidopsis plasmodesmal proteome. | KEEP AS NON CORE | Summary: ABCB1 was detected in a plasmodesmata-enriched proteomic fraction. Reason: The original TableS1 contains AT2G36910.1 with two unique peptides and 2.95% coverage. Retain the HDA location at that resolution; the study does not independently image ABCB1 at plasmodesmata or demonstrate exclusive residence or plasmodesmal transport function. General fraction contamination is not target-specific counterevidence. Supporting Evidence: file:ARATH/ABCB1/ABCB1-source-analysis/README.md ABCB1 AT2G36910.1 at row2168 with 2 unique peptides and 2.95% coverage |
| GO:0009555 pollen development | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1 and ABCB19 jointly support pollen and male-gametophyte development. Reason: The full study directly measures pollen number, viability and abnormal nuclear morphology in the double mutant. Retain the shared developmental contribution of ABCB1-mediated transport without claiming single-gene indispensability or transferring the TWD1-specific cell-plate defect to ABCB1. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant |
| GO:0009555 pollen development | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB1 and ABCB19 jointly support pollen and male-gametophyte development. Reason: The full study directly measures pollen number, viability and abnormal nuclear morphology in the double mutant. Retain the shared developmental contribution of ABCB1-mediated transport without claiming single-gene indispensability or transferring the TWD1-specific cell-plate defect to ABCB1. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant |
| GO:0009624 response to nematode | HEP PMID:16478044 Nematode-induced changes of transporter gene expression in A... | UNDECIDED | Summary: The nematode-response expression annotation remains functionally unresolved. Reason: The accessible PMID16478044 abstract describes an infection time-course expression screen and targeted qPCR, but the full target-level evidence could not be recovered despite normal and publisher-PDF attempts. Induced or repressed expression does not alone identify the work ABCB1 performs in host response; do not reject a curator claim without the missing target details. Supporting Evidence: PMID:16478044 Expression of 50 transporter genes from 18 different gene families was significantly changed upon nematode infestation. |
| GO:0009637 response to blue light | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1 modulates blue-light growth responses. Reason: The full primary directly assays atpgp1 mutants under blue illumination and finds altered hypocotyl inhibition. This supports a downstream hormone-transport contribution to the response, not light absorption by ABCB1. Supporting Evidence: url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation |
| GO:0009637 response to blue light | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: ABCB1 modulates blue-light growth responses. Reason: The full primary directly assays atpgp1 mutants under blue illumination and finds altered hypocotyl inhibition. This supports a downstream hormone-transport contribution to the response, not light absorption by ABCB1. Supporting Evidence: url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation |
| GO:0009639 response to red or far red light | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: ABCB1 modulates red and far-red growth responses. Reason: The atpgp1 mutant, not only the stronger atmdr1 mutant, is assayed under red/far-red light. Retain the physiological response without assigning photoreceptor activity or transferring the AtMDR1-specific phyA epistasis experiment to ABCB1. Supporting Evidence: url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation |
| GO:0009640 photomorphogenesis | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1-mediated hormone transport contributes to photomorphogenesis. Reason: Mutant hypocotyl responses and pigment accumulation connect this transporter to light-dependent seedling development. These effects are broader downstream outcomes of transport and do not make ABCB1 a universal light-signaling component. Supporting Evidence: url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ both the atmdr1-100 and atpgp1-100 mutants accumulated less anthocyanin under continuous far-red and blue light |
| GO:0009640 photomorphogenesis | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: ABCB1-mediated hormone transport contributes to photomorphogenesis. Reason: Mutant hypocotyl responses and pigment accumulation connect this transporter to light-dependent seedling development. These effects are broader downstream outcomes of transport and do not make ABCB1 a universal light-signaling component. Supporting Evidence: url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ both the atmdr1-100 and atpgp1-100 mutants accumulated less anthocyanin under continuous far-red and blue light |
| GO:0009733 response to auxin | IEA GO_REF:0000117 | ACCEPT | Summary: ABCB1 contributes to auxin responses by controlling hormone movement. Reason: Native growth and auxin-reporter phenotypes complement direct IAA export measurements. This is transport-mediated participation in the response, not evidence that ABCB1 is a nuclear auxin receptor or that every light phenotype is exclusively auxin-mediated. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation |
| GO:0009733 response to auxin | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | ACCEPT | Summary: ABCB1 contributes to auxin responses by controlling hormone movement. Reason: Native growth and auxin-reporter phenotypes complement direct IAA export measurements. This is transport-mediated participation in the response, not evidence that ABCB1 is a nuclear auxin receptor or that every light phenotype is exclusively auxin-mediated. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation |
| GO:0009741 response to brassinosteroid | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: ABCB1 directly transports bioactive brassinosteroids and contributes to their responses. Reason: PMID38513023 primarily characterizes ABCB19 biochemistry but includes native ABCB1 gain/loss and BR-signaling experiments. Independent PMID39497419 directly establishes ABCB1 ATP-dependent BL transport, CSA export and ligand recognition. These combined sources support the existing BR-response claim; they do not transfer every ABCB19 biochemical measurement to ABCB1. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:0009741 response to brassinosteroid | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ABCB1 directly transports bioactive brassinosteroids and contributes to their responses. Reason: PMID38513023 primarily characterizes ABCB19 biochemistry but includes native ABCB1 gain/loss and BR-signaling experiments. Independent PMID39497419 directly establishes ABCB1 ATP-dependent BL transport, CSA export and ligand recognition. These combined sources support the existing BR-response claim; they do not transfer every ABCB19 biochemical measurement to ABCB1. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:0009741 response to brassinosteroid | IEA GO_REF:0000117 | ACCEPT | Summary: ABCB1 directly transports bioactive brassinosteroids and contributes to their responses. Reason: PMID38513023 primarily characterizes ABCB19 biochemistry but includes native ABCB1 gain/loss and BR-signaling experiments. Independent PMID39497419 directly establishes ABCB1 ATP-dependent BL transport, CSA export and ligand recognition. These combined sources support the existing BR-response claim; they do not transfer every ABCB19 biochemical measurement to ABCB1. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:0009741 response to brassinosteroid | IMP PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: ABCB1 directly transports bioactive brassinosteroids and contributes to their responses. Reason: PMID38513023 primarily characterizes ABCB19 biochemistry but includes native ABCB1 gain/loss and BR-signaling experiments. Independent PMID39497419 directly establishes ABCB1 ATP-dependent BL transport, CSA export and ligand recognition. These combined sources support the existing BR-response claim; they do not transfer every ABCB19 biochemical measurement to ABCB1. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:0009741 response to brassinosteroid | IMP PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ABCB1 directly transports bioactive brassinosteroids and contributes to their responses. Reason: PMID38513023 primarily characterizes ABCB19 biochemistry but includes native ABCB1 gain/loss and BR-signaling experiments. Independent PMID39497419 directly establishes ABCB1 ATP-dependent BL transport, CSA export and ligand recognition. These combined sources support the existing BR-response claim; they do not transfer every ABCB19 biochemical measurement to ABCB1. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:0009926 auxin polar transport | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ABCB1 auxin export contributes to tissue-level polar auxin transport. Reason: Native transport defects, direct cell export assays and functional interactions support participation in the polar transport system. PM polarity of the carrier itself need not be uniform or sufficient to determine whole-tissue flux, and the negative purified-proteoliposome result is retained as an assay-specific limitation. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system PMID:16212599 Protoplasts from Arabidopsis pgp1 leaf mesophyll cells exhibit reduced efflux of natural and synthetic auxins |
| GO:0009926 auxin polar transport | IEA GO_REF:0000117 | ACCEPT | Summary: ABCB1 auxin export contributes to tissue-level polar auxin transport. Reason: Native transport defects, direct cell export assays and functional interactions support participation in the polar transport system. PM polarity of the carrier itself need not be uniform or sufficient to determine whole-tissue flux, and the negative purified-proteoliposome result is retained as an assay-specific limitation. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system PMID:16212599 Protoplasts from Arabidopsis pgp1 leaf mesophyll cells exhibit reduced efflux of natural and synthetic auxins |
| GO:0009926 auxin polar transport | IMP PMID:16212599 Cellular efflux of auxin catalyzed by the Arabidopsis MDR/PG... | ACCEPT | Summary: ABCB1 auxin export contributes to tissue-level polar auxin transport. Reason: Native transport defects, direct cell export assays and functional interactions support participation in the polar transport system. PM polarity of the carrier itself need not be uniform or sufficient to determine whole-tissue flux, and the negative purified-proteoliposome result is retained as an assay-specific limitation. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system PMID:16212599 Protoplasts from Arabidopsis pgp1 leaf mesophyll cells exhibit reduced efflux of natural and synthetic auxins |
| GO:0009926 auxin polar transport | TAS PMID:16359667 The ABC of auxin transport: the role of p-glycoproteins in p... | ACCEPT | Summary: ABCB1 auxin export contributes to tissue-level polar auxin transport. Reason: Native transport defects, direct cell export assays and functional interactions support participation in the polar transport system. PM polarity of the carrier itself need not be uniform or sufficient to determine whole-tissue flux, and the negative purified-proteoliposome result is retained as an assay-specific limitation. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system PMID:16212599 Protoplasts from Arabidopsis pgp1 leaf mesophyll cells exhibit reduced efflux of natural and synthetic auxins |
| GO:0010315 auxin export across the plasma membrane | IDA PMID:23147222 Arabidopsis ABCB21 is a facultative auxin importer/exporter ... | ACCEPT | Summary: ABCB1 exports IAA from cells. Reason: The complete comparative 2012 author manuscript explicitly includes ABCB1 as an efflux comparator in both loading and export formats. The 2024 cell-loading experiment independently corroborates export with TWD1; lack of purified IAA transport under one reconstitution condition does not negate the cellular activity. Supporting Evidence: url:https://repository.kulib.kyoto-u.ac.jp/server/api/core/bitstreams/84e4c3dc-3d35-44e3-9a2a-68ccecf0ee0c/content ABCB1 clearly reveals efflux activity for IAA, while ABCB21 as well as ABCB4 show uptake activity in this assay. PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system |
| GO:0010315 auxin export across the plasma membrane | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ABCB1 exports IAA from cells. Reason: The complete comparative 2012 author manuscript explicitly includes ABCB1 as an efflux comparator in both loading and export formats. The 2024 cell-loading experiment independently corroborates export with TWD1; lack of purified IAA transport under one reconstitution condition does not negate the cellular activity. Supporting Evidence: url:https://repository.kulib.kyoto-u.ac.jp/server/api/core/bitstreams/84e4c3dc-3d35-44e3-9a2a-68ccecf0ee0c/content ABCB1 clearly reveals efflux activity for IAA, while ABCB21 as well as ABCB4 show uptake activity in this assay. PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system |
| GO:0010328 auxin influx transmembrane transporter activity | IDA PMID:23147222 Arabidopsis ABCB21 is a facultative auxin importer/exporter ... | MODIFY | Summary: The cited comparative experiment supports ABCB1 efflux, not influx. Reason: Reading the complete PMID23147222 Results resolves the direction: in the import/loading assay, ABCB1 lowers IAA retention through efflux, whereas ABCB4/21 raise retention through uptake. Calling an experiment an import assay does not make every tested protein an importer. Correct to the already supported auxin efflux MF using the actual same-target comparison, not title-based paralog exclusion. Proposed replacements: auxin efflux transmembrane transporter activity Supporting Evidence: url:https://repository.kulib.kyoto-u.ac.jp/server/api/core/bitstreams/84e4c3dc-3d35-44e3-9a2a-68ccecf0ee0c/content ABCB1 clearly reveals efflux activity for IAA, while ABCB21 as well as ABCB4 show uptake activity in this assay. |
| GO:0010329 auxin efflux transmembrane transporter activity | IDA PMID:16212599 Cellular efflux of auxin catalyzed by the Arabidopsis MDR/PG... | ACCEPT | Summary: ABCB1 has directly supported auxin efflux activity. Reason: Native protoplast and heterologous cell assays, including the explicit ABCB1 comparator in PMID23147222, establish outward IAA transport. The 2024 study reports both positive cell-based export with TWD1 and negative purified proteoliposome transport; the mechanistic cause of this system dependence is unresolved. Supporting Evidence: url:https://repository.kulib.kyoto-u.ac.jp/server/api/core/bitstreams/84e4c3dc-3d35-44e3-9a2a-68ccecf0ee0c/content ABCB1 clearly reveals efflux activity for IAA, while ABCB21 as well as ABCB4 show uptake activity in this assay. PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system |
| GO:0010329 auxin efflux transmembrane transporter activity | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ABCB1 has directly supported auxin efflux activity. Reason: Native protoplast and heterologous cell assays, including the explicit ABCB1 comparator in PMID23147222, establish outward IAA transport. The 2024 study reports both positive cell-based export with TWD1 and negative purified proteoliposome transport; the mechanistic cause of this system dependence is unresolved. Supporting Evidence: url:https://repository.kulib.kyoto-u.ac.jp/server/api/core/bitstreams/84e4c3dc-3d35-44e3-9a2a-68ccecf0ee0c/content ABCB1 clearly reveals efflux activity for IAA, while ABCB21 as well as ABCB4 show uptake activity in this assay. PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system |
| GO:0010329 auxin efflux transmembrane transporter activity | IEA GO_REF:0000117 | ACCEPT | Summary: ABCB1 has directly supported auxin efflux activity. Reason: Native protoplast and heterologous cell assays, including the explicit ABCB1 comparator in PMID23147222, establish outward IAA transport. The 2024 study reports both positive cell-based export with TWD1 and negative purified proteoliposome transport; the mechanistic cause of this system dependence is unresolved. Supporting Evidence: url:https://repository.kulib.kyoto-u.ac.jp/server/api/core/bitstreams/84e4c3dc-3d35-44e3-9a2a-68ccecf0ee0c/content ABCB1 clearly reveals efflux activity for IAA, while ABCB21 as well as ABCB4 show uptake activity in this assay. PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 No active transport of IAA or IBA was detected in this proteoliposome-based assay system |
| GO:0010928 regulation of auxin mediated signaling pathway | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB1-dependent auxin transport influences signaling outputs in reproductive tissues. Reason: The double-mutant transport and developmental data support hormone-distribution-mediated regulation. Detailed nectary DR5/starch defects are TWD1-specific in this study and cannot be assigned to ABCB1 from proximity in the pathway; the retained claim is the broader transport-mediated effect. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone url:https://oup.silverchair-cdn.com/article-minimal/6581225 altered PAT in filaments is responsible for altered auxin responses |
| GO:0016020 membrane | IBA GO_REF:0000033 | MODIFY | Summary: The general membrane assertion can be refined to the functional plasma membrane. Reason: PTN002517083 correctly places ABCB1 in a membrane. Direct native localization resolves the PM and independent ER retention is described separately; this refinement does not invalidate the inherited membrane claim. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN002517083 SUPPORTS TRANSFER The ancestral membrane function is valid and refined by direct ABCB1 localization. Proposed replacements: plasma membrane Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: The general membrane assertion can be refined to the functional plasma membrane. Reason: PTN002517083 correctly places ABCB1 in a membrane. Direct native localization resolves the PM and independent ER retention is described separately; this refinement does not invalidate the inherited membrane claim. Proposed replacements: plasma membrane Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0016887 ATP hydrolysis activity | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ATP hydrolysis is intrinsic to ABCB1 transport. Reason: Direct purified ABCB1 ATPase assays, catalytic EQ mutants, vanadate sensitivity and ATP-dependent BL transport support this core activity. The ABCB19 ISS donor is independently experimentally characterized, and direct ABCB1 data now corroborate the shared reaction rather than relying solely on transfer. Supporting Evidence: PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0016887 ATP hydrolysis activity | IEA GO_REF:0000120 | ACCEPT | Summary: ATP hydrolysis is intrinsic to ABCB1 transport. Reason: Direct purified ABCB1 ATPase assays, catalytic EQ mutants, vanadate sensitivity and ATP-dependent BL transport support this core activity. The ABCB19 ISS donor is independently experimentally characterized, and direct ABCB1 data now corroborate the shared reaction rather than relying solely on transfer. Supporting Evidence: PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0016887 ATP hydrolysis activity | IMP PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ATP hydrolysis is intrinsic to ABCB1 transport. Reason: Direct purified ABCB1 ATPase assays, catalytic EQ mutants, vanadate sensitivity and ATP-dependent BL transport support this core activity. The ABCB19 ISS donor is independently experimentally characterized, and direct ABCB1 data now corroborate the shared reaction rather than relying solely on transfer. Supporting Evidence: PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0016887 ATP hydrolysis activity | ISS PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: ATP hydrolysis is intrinsic to ABCB1 transport. Reason: Direct purified ABCB1 ATPase assays, catalytic EQ mutants, vanadate sensitivity and ATP-dependent BL transport support this core activity. The ABCB19 ISS donor is independently experimentally characterized, and direct ABCB1 data now corroborate the shared reaction rather than relying solely on transfer. Supporting Evidence: PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0042626 ATPase-coupled transmembrane transporter activity | IBA GO_REF:0000033 | MODIFY | Summary: ATPase-coupled transport can be refined to the demonstrated ABC-type mechanism. Reason: The full-length two-NBD/two-TMD architecture and direct nucleotide-dependent transport support the existing ABC-type transporter term. PTN000657189 places the broader energy-coupled activity correctly; the 2001 inventory is classification support, while the later target biochemistry establishes mechanism. Propagation Review Root cause: NO FAILURE CORE Sources checked: PANTHER:PTN000657189 SUPPORTS TRANSFER Broad ATP-dependent transporter inheritance is sound; target structure and catalysis establish the ABC-type refinement. Proposed replacements: ABC-type transporter activity Supporting Evidence: PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. PMID:39497419 the ATP plus BL-bound structure of ABCB1 |
| GO:0042626 ATPase-coupled transmembrane transporter activity | ISS PMID:11346655 The Arabidopsis thaliana ABC protein superfamily, a complete... | MODIFY | Summary: ATPase-coupled transport can be refined to the demonstrated ABC-type mechanism. Reason: The full-length two-NBD/two-TMD architecture and direct nucleotide-dependent transport support the existing ABC-type transporter term. PTN000657189 places the broader energy-coupled activity correctly; the 2001 inventory is classification support, while the later target biochemistry establishes mechanism. Proposed replacements: ABC-type transporter activity Supporting Evidence: PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. PMID:39497419 the ATP plus BL-bound structure of ABCB1 |
| GO:0043481 anthocyanin accumulation in tissues in response to UV light | IEA GO_REF:0000117 | UNDECIDED | Summary: The UV-specific anthocyanin response remains unresolved after identifying the cited experimentβs actual stimuli. Reason: The complete PMID15908594 Figure3C and Methods use continuous far-red and blue LED illumination for anthocyanin measurements. UV-A appears in background photoreceptor discussion, not as the tested pigment stimulus. This identifies a source-to-claim gap but does not demonstrate absence of a biological UV response; no independent target-specific UV evidence was recovered. Retain uncertainty, consistent with the ABCB19 assessment, while keeping the demonstrated blue/far-red responses separately. Supporting Evidence: url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ Seedlings (approximately 100) were grown in continuous far-red or blue light for 4 d before anthocyanin extraction. |
| GO:0043481 anthocyanin accumulation in tissues in response to UV light | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | UNDECIDED | Summary: The UV-specific anthocyanin response remains unresolved after identifying the cited experimentβs actual stimuli. Reason: The complete PMID15908594 Figure3C and Methods use continuous far-red and blue LED illumination for anthocyanin measurements. UV-A appears in background photoreceptor discussion, not as the tested pigment stimulus. This identifies a source-to-claim gap but does not demonstrate absence of a biological UV response; no independent target-specific UV evidence was recovered. Retain uncertainty, consistent with the ABCB19 assessment, while keeping the demonstrated blue/far-red responses separately. Supporting Evidence: url:https://pmc.ncbi.nlm.nih.gov/articles/PMC1150410/ Seedlings (approximately 100) were grown in continuous far-red or blue light for 4 d before anthocyanin extraction. |
| GO:0048229 gametophyte development | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB1 and ABCB19 jointly support pollen and male-gametophyte development. Reason: The full study directly measures pollen number, viability and abnormal nuclear morphology in the double mutant. Retain the shared developmental contribution of ABCB1-mediated transport without claiming single-gene indispensability or transferring the TWD1-specific cell-plate defect to ABCB1. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant |
| GO:0048439 flower morphogenesis | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB1 contributes with ABCB19 to flower and stamen development. Reason: The double-mutant and native localization studies support shared control of filament elongation and reproductive development. The evidence does not establish an obligatory ABCB1-only route; loss of short-stamen number and nectary starch is specific to twd1 in the 2022 comparison and is not attributed to ABCB1 here. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0048443 stamen development | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1 contributes with ABCB19 to flower and stamen development. Reason: The double-mutant and native localization studies support shared control of filament elongation and reproductive development. The evidence does not establish an obligatory ABCB1-only route; loss of short-stamen number and nectary starch is specific to twd1 in the 2022 comparison and is not attributed to ABCB1 here. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0048443 stamen development | IGI PMID:18628351 Auxin regulates Arabidopsis anther dehiscence, pollen matura... | KEEP AS NON CORE | Summary: ABCB1 contributes with ABCB19 to flower and stamen development. Reason: The double-mutant and native localization studies support shared control of filament elongation and reproductive development. The evidence does not establish an obligatory ABCB1-only route; loss of short-stamen number and nectary starch is specific to twd1 in the 2022 comparison and is not attributed to ABCB1 here. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0048443 stamen development | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB1 contributes with ABCB19 to flower and stamen development. Reason: The double-mutant and native localization studies support shared control of filament elongation and reproductive development. The evidence does not establish an obligatory ABCB1-only route; loss of short-stamen number and nectary starch is specific to twd1 in the 2022 comparison and is not attributed to ABCB1 here. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0048461 flower structural organization | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1 contributes with ABCB19 to flower and stamen development. Reason: The double-mutant and native localization studies support shared control of filament elongation and reproductive development. The evidence does not establish an obligatory ABCB1-only route; loss of short-stamen number and nectary starch is specific to twd1 in the 2022 comparison and is not attributed to ABCB1 here. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0048461 flower structural organization | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB1 contributes with ABCB19 to flower and stamen development. Reason: The double-mutant and native localization studies support shared control of filament elongation and reproductive development. The evidence does not establish an obligatory ABCB1-only route; loss of short-stamen number and nectary starch is specific to twd1 in the 2022 comparison and is not attributed to ABCB1 here. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced url:https://oup.silverchair-cdn.com/article-minimal/6581225 both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant url:https://oup.silverchair-cdn.com/article-minimal/6581225 both TWD1βCFP and ABCB1βGFP localized on the endothecium and middle layer plasma membrane |
| GO:0051510 regulation of unidimensional cell growth | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1 and ABCB19 regulate longitudinal cell growth in stamens. Reason: The double mutant has directly measured shorter and wider filament epidermal cells. Transport-mediated control of one-dimensional growth is justified, while acquisition of epidermal identity is a different claim. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced |
| GO:0051510 regulation of unidimensional cell growth | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB1 and ABCB19 regulate longitudinal cell growth in stamens. Reason: The double mutant has directly measured shorter and wider filament epidermal cells. Transport-mediated control of one-dimensional growth is justified, while acquisition of epidermal identity is a different claim. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced |
| GO:0055085 transmembrane transport | IBA GO_REF:0000033 | ACCEPT | Summary: ABCB1 performs ATP-dependent transmembrane transport of two distinct hormone classes. Reason: The general process appropriately covers both IAA and brassinosteroid movement across the PM. The separate auxin-export process captures only one substrate class; retaining this aggregate claim does not infer a third substrate or duplicate a false activity. PTN000657189 is consistent with directly demonstrated conserved membrane transport. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0055085 transmembrane transport | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ABCB1 performs ATP-dependent transmembrane transport of two distinct hormone classes. Reason: The general process appropriately covers both IAA and brassinosteroid movement across the PM. The separate auxin-export process captures only one substrate class; retaining this aggregate claim does not infer a third substrate or duplicate a false activity. PTN000657189 is consistent with directly demonstrated conserved membrane transport. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0055085 transmembrane transport | IEA GO_REF:0000002 | ACCEPT | Summary: ABCB1 performs ATP-dependent transmembrane transport of two distinct hormone classes. Reason: The general process appropriately covers both IAA and brassinosteroid movement across the PM. The separate auxin-export process captures only one substrate class; retaining this aggregate claim does not infer a third substrate or duplicate a false activity. PTN000657189 is consistent with directly demonstrated conserved membrane transport. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0055085 transmembrane transport | IMP PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ABCB1 performs ATP-dependent transmembrane transport of two distinct hormone classes. Reason: The general process appropriately covers both IAA and brassinosteroid movement across the PM. The separate auxin-export process captures only one substrate class; retaining this aggregate claim does not infer a third substrate or duplicate a false activity. PTN000657189 is consistent with directly demonstrated conserved membrane transport. Supporting Evidence: PMID:39497419 cells expressing both ABCB1 and TWD1 accumulated less [3H]-IAA than those expressing TWD1 alone PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. |
| GO:0060919 auxin import into cell | IEA GO_REF:0000108 | MODIFY | Summary: The electronic auxin-import process inherits a reversed direction from the influx annotation. Reason: The direct target comparison in PMID23147222 shows ABCB1 efflux even in the import/loading assay. Correct to auxin efflux, matching the original export rows and avoiding transfer of ABCB4/21 conditional uptake to ABCB1. Proposed replacements: auxin export across the plasma membrane Supporting Evidence: url:https://repository.kulib.kyoto-u.ac.jp/server/api/core/bitstreams/84e4c3dc-3d35-44e3-9a2a-68ccecf0ee0c/content ABCB1 clearly reveals efflux activity for IAA, while ABCB21 as well as ABCB4 show uptake activity in this assay. |
| GO:0090627 plant epidermal cell differentiation | IEA GO_REF:0000117 | MARK AS OVER ANNOTATED | Summary: The cited stamen study measures growth of epidermal cells rather than their differentiation. Reason: Figure1 quantifies length and width of existing epidermal cells in abcb1abcb19. It does not establish an epidermal cell-fate transition. The supported size and one-dimensional-growth roles are retained separately; this is a source-specific interpretation limit, not a categorical exclusion of developmental effects. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced |
| GO:0090627 plant epidermal cell differentiation | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | MARK AS OVER ANNOTATED | Summary: The cited stamen study measures growth of epidermal cells rather than their differentiation. Reason: Figure1 quantifies length and width of existing epidermal cells in abcb1abcb19. It does not establish an epidermal cell-fate transition. The supported size and one-dimensional-growth roles are retained separately; this is a source-specific interpretation limit, not a categorical exclusion of developmental effects. Supporting Evidence: url:https://oup.silverchair-cdn.com/article-minimal/6581225 the length of epidermal cells in the middle of twd (138.3 Β± 1.7 ΞΌm) and abcb1abcb19 stamen (142.0 Β± 2.2 ΞΌm) was significantly reduced |
| GO:0140359 ABC-type transporter activity | IEA GO_REF:0000002 | ACCEPT | Summary: ABCB1 is a structurally and biochemically characterized ABC-type transporter. Reason: Direct ABCB1 structures resolve its two membrane and nucleotide-binding halves, and ATP-dependent hormone transport tests establish function. The experimentally grounded ABCB19 donor supports conserved mechanism but is no longer the sole basis of this claim. Supporting Evidence: PMID:39497419 the ATP plus BL-bound structure of ABCB1 PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA |
| GO:0140359 ABC-type transporter activity | ISS PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: ABCB1 is a structurally and biochemically characterized ABC-type transporter. Reason: Direct ABCB1 structures resolve its two membrane and nucleotide-binding halves, and ATP-dependent hormone transport tests establish function. The experimentally grounded ABCB19 donor supports conserved mechanism but is no longer the sole basis of this claim. Supporting Evidence: PMID:39497419 the ATP plus BL-bound structure of ABCB1 PMID:39497419 ABCB1 can transport bioactive BR in vitro using the energy of ATP hydrolysis. PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA |
| GO:1900459 positive regulation of brassinosteroid mediated signaling pathway | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB1 supports BR signaling by controlling extracellular ligand availability. Reason: GO:1900459 denotes positive regulation of BR signaling, not BR homeostasis or receptor activity. PMID:38513023 establishes altered BES1 activation in abcb19 and abcb1 abcb19 mutants and enhanced signaling in ABCB1/ABCB19 overexpression lines; PMID:39497419 establishes ABCB1 BR export and includes ABCB19 comparisons. Thus the regulatory claim is supported, rather than contradicted because the transporter acts upstream of BRI1. Retain it as a non-core signaling consequence of the directly established BR-export activity, consistently for both paralogs; the transport molecular function remains core. This does not assign BRI1 signal-transduction chemistry to ABCB1, nor resolve the BR-versus-auxin contribution to every growth phenotype. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:1900459 positive regulation of brassinosteroid mediated signaling pathway | IMP PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | KEEP AS NON CORE | Summary: ABCB1 supports BR signaling by controlling extracellular ligand availability. Reason: GO:1900459 denotes positive regulation of BR signaling, not BR homeostasis or receptor activity. PMID:38513023 establishes altered BES1 activation in abcb19 and abcb1 abcb19 mutants and enhanced signaling in ABCB1/ABCB19 overexpression lines; PMID:39497419 establishes ABCB1 BR export and includes ABCB19 comparisons. Thus the regulatory claim is supported, rather than contradicted because the transporter acts upstream of BRI1. Retain it as a non-core signaling consequence of the directly established BR-export activity, consistently for both paralogs; the transport molecular function remains core. This does not assign BRI1 signal-transduction chemistry to ABCB1, nor resolve the BR-versus-auxin contribution to every growth phenotype. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:1900459 positive regulation of brassinosteroid mediated signaling pathway | IMP PMID:39497419 Structural insights into brassinosteroid export mediated by ... | KEEP AS NON CORE | Summary: ABCB1 supports BR signaling by controlling extracellular ligand availability. Reason: GO:1900459 denotes positive regulation of BR signaling, not BR homeostasis or receptor activity. PMID:38513023 establishes altered BES1 activation in abcb19 and abcb1 abcb19 mutants and enhanced signaling in ABCB1/ABCB19 overexpression lines; PMID:39497419 establishes ABCB1 BR export and includes ABCB19 comparisons. Thus the regulatory claim is supported, rather than contradicted because the transporter acts upstream of BRI1. Retain it as a non-core signaling consequence of the directly established BR-export activity, consistently for both paralogs; the transport molecular function remains core. This does not assign BRI1 signal-transduction chemistry to ABCB1, nor resolve the BR-versus-auxin contribution to every growth phenotype. Supporting Evidence: PMID:39497419 protoplasts expressing ABCB1WT-GFP showed enhanced export of CSA PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
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Download this section (compressed HTML)Q: Which membrane environment and partner state enable ABCB1 auxin export while purified ABCB1 readily transports BR but fails to transport IAA in proteoliposomes?
Q: What fraction of each ABCB1/19 developmental phenotype is mediated by auxin redistribution versus brassinosteroid export?
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