ABCB19 is a full-size ABCB transporter with two nucleotide-binding and two transmembrane domains. At the plasma membrane it supports cellular auxin export and long-distance auxin distribution, including basipetal transport in shoots and acropetal transport through roots. Where ABCB19 and PIN1 overlap, their interaction can stabilize PIN1 and alter transport efficiency; ABCB19 also acts outside those overlapping domains. ABCB19 directly exports bioactive brassinosteroids, supplying extracellular hormone for BR signaling. Purified-protein studies readily demonstrate BR transport but did not detect IAA transport under the same reconstitution conditions, whereas cells expressing ABCB19 with TWD1 show IAA export. Its physiological effects include light-dependent growth, lateral-root elongation, organ-boundary formation, late stamen elongation and shoot branching.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005515 protein binding | IPI PMID:17237354 Interactions among PIN-FORMED and P-glycoprotein auxin trans... | REMOVE | Summary: Interaction of ABCB19/PGP19 with PIN1 in yeast two-hybrid and co-immunoprecipitation assays; PGP19 stabilizes PIN1 in sterol/sphingolipid-enriched membrane domains. Reason: PIN1βABCB19 interaction and functional coupling are real, but bare protein binding does not specify the transport reaction or its regulation. REMOVE follows the uninformative-binding policy, not rejection of the interaction. Supporting Evidence: PMID:17237354 Specific PGP-PIN interactions were seen in yeast two-hybrid and coimmunoprecipitation assays. |
| GO:0005524 ATP binding | IEA GO_REF:0000002 | ACCEPT | Summary: ATP binding by the two nucleotide-binding domains. Reason: ATP binding is integral to the two nucleotide-binding domains and the measured ATP-hydrolysis-coupled transport cycle. It is a core biochemical property, not peripheral simply because it is binding. Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0005634 nucleus | ISM GO_REF:0000122 | MARK AS OVER ANNOTATED | Summary: The AtSubP nuclear assignment overextends sequence prediction for the intact ABCB19 membrane transporter. Reason: AtSubP is an ISM compartment prediction; experimental-curator deference does not apply. Native PGP19/ABCB19 imaging with PIN proteins (PMID:17237354) and the membrane-embedded BR transporter structure (PMID:38513023) support an integral plasma-membrane transporter. 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 |
| GO:0005829 cytosol | HDA PMID:28887381 Global Analysis of Membrane-associated Protein Oligomerizati... | MARK AS OVER ANNOTATED | Summary: The membrane-profiling source does not establish a cytosolic ABCB19 pool. Reason: All seven original supplemental workbooks were inspected. S1 Mapp rows 2145 and 2804 list AT3G28860 as True membrane, with blank Dual Localized and SUBAcon plasma membrane; S4 sucrose profiles support membrane association. Cholate-soluble material here is detergent-extracted microsomal protein, not an independently demonstrated cytosolic pool. The cytosol annotation overinterprets this source; a 12-TM architecture alone was not used to declare the location impossible. Supporting Evidence: file:ARATH/ABCB19/ABCB19-bioinformatics/README.md Cholate-soluble material is therefore not synonymous with cytosol. |
| GO:0005886 plasma membrane | HDA PMID:16618929 Mapping the Arabidopsis organelle proteome. | ACCEPT | Summary: LOPIT organelle proteomics assigned ABCB19 to the plasma membrane. Reason: Consistent with core location. Supporting Evidence: PMID:16618929 enabling confident and simultaneous localization of 527 proteins to the endoplasmic reticulum, Golgi apparatus, vacuolar membrane, plasma membrane, or mitochondria and plastids |
| GO:0005886 plasma membrane | HDA PMID:22923678 Putative glycosyltransferases and other plant Golgi apparatu... | ACCEPT | Summary: LOPIT proteomics assigned ABCB19 to the plasma membrane. Reason: Consistent with core location. Supporting Evidence: PMID:22923678 the localization of 304 endoplasmic reticulum and 208 plasma membrane proteins |
| GO:0005886 plasma membrane | IDA PMID:16601150 PIN proteins perform a rate-limiting function in cellular au... | ACCEPT | Summary: Plasma membrane localization. Reason: Core location. Supporting Evidence: PMID:16601150 Plant-specific pin-formed (PIN) proteins and several phosphoglycoprotein (PGP) transporters are crucial factors in auxin transport-related development |
| GO:0005886 plasma membrane | IEA GO_REF:0000120 | ACCEPT | Summary: Plasma membrane by ARBA/UniProt subcellular location. Reason: Core location. 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 |
| GO:0005886 plasma membrane | ISS GO_REF:0000024 | ACCEPT | Summary: Plasma membrane transferred from ABCB1. Reason: Consistent with direct evidence for ABCB19. 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 |
| GO:0008361 regulation of cell size | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ARBA rule for regulation of cell size (hypocotyl cell elongation phenotypes). The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: The independently supported developmental role is retained across the electronic and experimental rows for this same claim. It is contextual to hormone distribution by ABCB19, rather than a separate transport-independent catalytic or receptor activity. Supporting Evidence: PMID:15908594 loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation |
| GO:0008361 regulation of cell size | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: Hypocotyl cell elongation altered in atmdr1. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native atmdr1/abcb19 mutants alter light-dependent hypocotyl elongation, pigment accumulation, auxin-sensitive root growth and gravitropic responses. Retain this contextual developmental response as non-core relative to the transport reaction; it does not make ABCB19 a light receptor. Supporting Evidence: PMID:15908594 loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation |
| GO:0009555 pollen development | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB19 contributes with ABCB1 to the auxin-distribution context of male gametophyte development. Reason: Full PMID:35512423 Fig.5 tests abcb1 abcb19 as well as twd1: the double mutant has reduced pollen number and viability and abnormal nuclei. This supports a contextual reproductive contribution of the transporters, not exclusive ABCB19 necessity or a direct pollen-mitosis enzyme. Failed cell plates/callose aggregation are TWD1-specific and are not assigned to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant but not in investigated pin mutants |
| GO:0009555 pollen development | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB19 contributes with ABCB1 to the auxin-distribution context of male gametophyte development. Reason: Full PMID:35512423 Fig.5 tests abcb1 abcb19 as well as twd1: the double mutant has reduced pollen number and viability and abnormal nuclei. This supports a contextual reproductive contribution of the transporters, not exclusive ABCB19 necessity or a direct pollen-mitosis enzyme. Failed cell plates/callose aggregation are TWD1-specific and are not assigned to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant but not in investigated pin mutants |
| GO:0009637 response to blue light | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ARBA rule for response to blue light. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: The independently supported developmental role is retained across the electronic and experimental rows for this same claim. It is contextual to hormone distribution by ABCB19, rather than a separate transport-independent catalytic or receptor activity. Supporting Evidence: PMID:32855213 abcb19 mutants develop irregularly wavy rosette leaves that are less sensitive to blue light-mediated leaf flattening |
| GO:0009637 response to blue light | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: atmdr1 hypersensitive to blue-light inhibition of hypocotyl elongation. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native atmdr1/abcb19 mutants alter light-dependent hypocotyl elongation, pigment accumulation, auxin-sensitive root growth and gravitropic responses. Retain this contextual developmental response as non-core relative to the transport reaction; it does not make ABCB19 a light receptor. Supporting Evidence: PMID:15908594 loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation |
| GO:0009637 response to blue light | IMP PMID:32855213 An ATP-Binding Cassette Transporter, ABCB19, Regulates Leaf ... | KEEP AS NON CORE | Summary: abcb19 leaf position and flattening are insensitive to blue light. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native abcb19 mutants have altered petiole angle and blue-light-dependent leaf flattening, associated with altered auxin transport/distribution. Retain this contextual response, distinguished from the placement of new leaf primordia. Supporting Evidence: PMID:32855213 abcb19 mutants develop irregularly wavy rosette leaves that are less sensitive to blue light-mediated leaf flattening |
| 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: atmdr1 hypersensitive to red/far-red inhibition of hypocotyl elongation. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native atmdr1/abcb19 mutants alter light-dependent hypocotyl elongation, pigment accumulation, auxin-sensitive root growth and gravitropic responses. Retain this contextual developmental response as non-core relative to the transport reaction; it does not make ABCB19 a light receptor. Supporting Evidence: PMID:15908594 loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation |
| GO:0009640 photomorphogenesis | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ARBA rule for photomorphogenesis. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: The independently supported developmental role is retained across the electronic and experimental rows for this same claim. It is contextual to hormone distribution by ABCB19, rather than a separate transport-independent catalytic or receptor activity. Supporting Evidence: PMID:15908594 loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation |
| GO:0009640 photomorphogenesis | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: Photomorphogenic defects in atmdr1. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native atmdr1/abcb19 mutants alter light-dependent hypocotyl elongation, pigment accumulation, auxin-sensitive root growth and gravitropic responses. Retain this contextual developmental response as non-core relative to the transport reaction; it does not make ABCB19 a light receptor. Supporting Evidence: PMID:15908594 loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation |
| GO:0009733 response to auxin | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ARBA rule for response to auxin. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: The independently supported developmental role is retained across the electronic and experimental rows for this same claim. It is contextual to hormone distribution by ABCB19, rather than a separate transport-independent catalytic or receptor activity. Supporting Evidence: PMID:15908594 increased root-growth sensitivity to 1-naphthalene acetic acid (1-NAA) |
| GO:0009733 response to auxin | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: atmdr1 roots are hypersensitive to NAA. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native atmdr1/abcb19 mutants alter light-dependent hypocotyl elongation, pigment accumulation, auxin-sensitive root growth and gravitropic responses. Retain this contextual developmental response as non-core relative to the transport reaction; it does not make ABCB19 a light receptor. Supporting Evidence: PMID:15908594 increased root-growth sensitivity to 1-naphthalene acetic acid (1-NAA) |
| GO:0009741 response to brassinosteroid | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | KEEP AS NON CORE | Summary: ABCB19-mediated BR export contributes to cellular brassinosteroid responses. Reason: The full ABCB19 primary shows altered BES1 dephosphorylation, BR-responsive expression and responses to exogenous brassinolide in abcb19-containing mutants, in addition to substrate-stimulated ATPase. This is a real physiological BR response mediated by transport, not merely substrate binding; retain it as a contextual process. Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0009741 response to brassinosteroid | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | KEEP AS NON CORE | Summary: ABCB19-mediated BR export contributes to cellular brassinosteroid responses. Reason: The full ABCB19 primary shows altered BES1 dephosphorylation, BR-responsive expression and responses to exogenous brassinolide in abcb19-containing mutants, in addition to substrate-stimulated ATPase. This is a real physiological BR response mediated by transport, not merely substrate binding; retain it as a contextual process. Supporting Evidence: PMID:39497419 ABCB19 functions as a BR exporter and, together with its close homolog ABCB1, positively regulates BR signaling |
| GO:0009741 response to brassinosteroid | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB19-mediated BR export contributes to cellular brassinosteroid responses. Reason: The full ABCB19 primary shows altered BES1 dephosphorylation, BR-responsive expression and responses to exogenous brassinolide in abcb19-containing mutants, in addition to substrate-stimulated ATPase. This is a real physiological BR response mediated by transport, not merely substrate binding; retain it as a contextual process. Supporting Evidence: 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... | KEEP AS NON CORE | Summary: ABCB19-mediated BR export contributes to cellular brassinosteroid responses. Reason: The full ABCB19 primary shows altered BES1 dephosphorylation, BR-responsive expression and responses to exogenous brassinolide in abcb19-containing mutants, in addition to substrate-stimulated ATPase. This is a real physiological BR response mediated by transport, not merely substrate binding; retain it as a contextual process. Supporting Evidence: PMID:38513023 ABCB19 and its close homolog, ABCB1, positively regulate brassinosteroid responses |
| GO:0009926 auxin polar transport | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: Cellular auxin export remains supported alongside direct brassinosteroid transport. Reason: The full 2024 primary includes HEK293F cells coexpressing ABCB19 and TWD1 with lower radiolabeled IAA accumulation than the TWD1-only control (Fig.S3F), consistent with export. Purified ABCB19 lacked detectable IAA binding, ATPase stimulation and active proteoliposome accumulation under the tested conditions; those negative assays constrain reconstitution, not the independently supported cellular transport function. Supporting Evidence: PMID:11701880 Auxin transport activity was greatly impaired in atmdr1 and atmdr1 atpgp1 double mutant plants. |
| GO:0009926 auxin polar transport | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA rule for auxin polar transport. Reason: Core process: ABCB19 drives long-distance basipetal auxin transport in shoots. Supporting Evidence: PMID:11701880 Auxin transport activity was greatly impaired in atmdr1 and atmdr1 atpgp1 double mutant plants. PMID:11701880 Epinastic cotyledons and reduced apical dominance were mutant phenotypes consistent with the disrupted basipetal flow of auxin. |
| GO:0009926 auxin polar transport | IMP PMID:11701880 Multidrug resistance-like genes of Arabidopsis required for ... | ACCEPT | Summary: Polar auxin transport is greatly impaired in atmdr1. Reason: Core process. Supporting Evidence: PMID:11701880 Auxin transport activity was greatly impaired in atmdr1 and atmdr1 atpgp1 double mutant plants. |
| GO:0009958 positive gravitropism | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: atmdr1 roots are hypergravitropic. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native atmdr1/abcb19 mutants alter light-dependent hypocotyl elongation, pigment accumulation, auxin-sensitive root growth and gravitropic responses. Retain this contextual developmental response as non-core relative to the transport reaction; it does not make ABCB19 a light receptor. Supporting Evidence: PMID:15908594 The atmdr1-100 and atmdr1-100/atpgp1-100 mutants also displayed enhanced root gravitropism. |
| GO:0010218 response to far red light | IMP PMID:15908594 Two homologous ATP-binding cassette transporter proteins, At... | KEEP AS NON CORE | Summary: atmdr1 is hypersensitive to far-red inhibition of hypocotyl elongation. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native atmdr1/abcb19 mutants alter light-dependent hypocotyl elongation, pigment accumulation, auxin-sensitive root growth and gravitropic responses. Retain this contextual developmental response as non-core relative to the transport reaction; it does not make ABCB19 a light receptor. Supporting Evidence: PMID:15908594 loss-of-function atmdr1 and atpgp1 mutants display hypersensitivity to far-red, red, and blue-light inhibition of hypocotyl elongation, reduced chlorophyll and anthocyanin accumulation |
| GO:0010315 auxin export across the plasma membrane | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: Cellular auxin export remains supported alongside direct brassinosteroid transport. Reason: The full 2024 primary includes HEK293F cells coexpressing ABCB19 and TWD1 with lower radiolabeled IAA accumulation than the TWD1-only control (Fig.S3F), consistent with export. Purified ABCB19 lacked detectable IAA binding, ATPase stimulation and active proteoliposome accumulation under the tested conditions; those negative assays constrain reconstitution, not the independently supported cellular transport function. Supporting Evidence: PMID:39497419 Auxin efflux activities of ABCB1 and ABCB19 have been demonstrated by either the reduced indole-3-acetic acid (IAA) export in Arabidopsis protoplasts isolated from abcb1, abcb19, and abcb1 abcb19 mutants or the increased IAA export in heterologous systems |
| GO:0010315 auxin export across the plasma membrane | IMP PMID:32855213 An ATP-Binding Cassette Transporter, ABCB19, Regulates Leaf ... | ACCEPT | Summary: Auxin transport measured in abcb19 protoplasts is reduced. Reason: Core process. Supporting Evidence: PMID:32855213 Visualization of auxin distribution, measurement of auxin transport in protoplasts, and direct quantification of free auxin levels suggest these irregularities are caused by misregulation of ABCB19-mediated auxin distribution |
| GO:0010329 auxin efflux transmembrane transporter activity | IDA PMID:16601150 PIN proteins perform a rate-limiting function in cellular au... | ACCEPT | Summary: Auxin efflux by PGP19/ABCB19 measured alongside PINs in heterologous and plant cells. Reason: Core MF. The cached PMID:16601150 record is abstract-only; the abstract states only that PIN-mediated efflux was distinguished from PGP-mediated efflux, and the PGP19-specific efflux measurements the curator used are in the full text, so we defer to the IDA. Independent ABCB19 efflux evidence is summarized in PMID:39497419. Supporting Evidence: PMID:16601150 the action of PINs in auxin efflux is distinct from PGP PMID:39497419 Auxin efflux activities of ABCB1 and ABCB19 have been demonstrated by either the reduced indole-3-acetic acid (IAA) export in Arabidopsis protoplasts isolated from abcb1, abcb19, and abcb1 abcb19 mutants or the increased IAA export in heterologous systems |
| GO:0010329 auxin efflux transmembrane transporter activity | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: Cellular auxin export remains supported alongside direct brassinosteroid transport. Reason: The full 2024 primary includes HEK293F cells coexpressing ABCB19 and TWD1 with lower radiolabeled IAA accumulation than the TWD1-only control (Fig.S3F), consistent with export. Purified ABCB19 lacked detectable IAA binding, ATPase stimulation and active proteoliposome accumulation under the tested conditions; those negative assays constrain reconstitution, not the independently supported cellular transport function. Supporting Evidence: PMID:39497419 Auxin efflux activities of ABCB1 and ABCB19 have been demonstrated by either the reduced indole-3-acetic acid (IAA) export in Arabidopsis protoplasts isolated from abcb1, abcb19, and abcb1 abcb19 mutants or the increased IAA export in heterologous systems |
| GO:0010329 auxin efflux transmembrane transporter activity | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA rule for auxin efflux transmembrane transporter activity. Reason: Core MF. Supporting Evidence: PMID:39497419 Auxin efflux activities of ABCB1 and ABCB19 have been demonstrated by either the reduced indole-3-acetic acid (IAA) export in Arabidopsis protoplasts isolated from abcb1, abcb19, and abcb1 abcb19 mutants or the increased IAA export in heterologous systems |
| GO:0010540 basipetal auxin transport | IMP PMID:11701880 Multidrug resistance-like genes of Arabidopsis required for ... | ACCEPT | Summary: atmdr1 (abcb19) inflorescence segments have impaired basipetal IAA transport; epinastic cotyledons and reduced apical dominance. Reason: Core: ABCB19 is a major contributor to long-distance basipetal auxin transport in shoots. Supporting Evidence: PMID:11701880 Auxin transport activity was greatly impaired in atmdr1 and atmdr1 atpgp1 double mutant plants. PMID:11701880 Epinastic cotyledons and reduced apical dominance were mutant phenotypes consistent with the disrupted basipetal flow of auxin. |
| GO:0010541 acropetal auxin transport | IMP PMID:17557805 Separating the roles of acropetal and basipetal auxin transp... | ACCEPT | Summary: mdr1 (abcb19) mutations reduce acropetal (rootward, central-cylinder) auxin transport in roots by 80%. Reason: Major quantitative transport role of ABCB19 in roots; core. Supporting Evidence: PMID:17557805 Mutations in Multidrug Resistance-Like1 (MDR1) reduced acropetal auxin transport in roots by 80% without affecting basipetal transport. |
| GO:0010928 regulation of auxin mediated signaling pathway | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: Altered auxin response in stamens of abcb mutants. Reason: Full primary DR5 reporter comparisons show altered auxin response distributions associated with ABCB19βGFP in the filament. The transporter contributes to the hormone-distribution context controlling signaling output; it is not itself the TIR1/AFB signaling receptor. Retain this regulatory contribution as non-core. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0016020 membrane | IBA GO_REF:0000033 | MODIFY | Summary: Membrane localization of ABCB transporters. Reason: Direct target imaging and membrane fractionation establish plasma membrane as the functional transport location. Refine the broad membrane term without inferring localization from the misleading mitochondrial name of the broad PANTHER family. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN002517083 SUPPORTS TRANSFER The actual PTHR43394 PAINT table supports this broad ancestral membrane/transport property. ABCB19 is legitimately among the experimental seeds. The target-specific replacement refines a true claim; it does not diagnose a faulty ancestral assertion or circular support. Proposed replacements: plasma membrane 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 |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: Membrane from InterPro. Reason: Direct target imaging and membrane fractionation establish plasma membrane as the functional transport location. Refine the broad membrane term without inferring localization from the misleading mitochondrial name of the broad PANTHER family. Proposed replacements: plasma membrane 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 |
| GO:0016887 ATP hydrolysis activity | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: ABCB19 ATP hydrolysis activity is potently stimulated by bioactive brassinosteroids. Reason: Correct; integral to ABC transport. Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0016887 ATP hydrolysis activity | IDA PMID:39497419 Structural insights into brassinosteroid export mediated by ... | ACCEPT | Summary: ATP hydrolysis by ABCB19 (comparator of ABCB1 in this BR-transport study). Reason: Correct activity, established directly in PMID:38513023. Supporting Evidence: PMID:39497419 ABCB19 functions as a BR exporter and, together with its close homolog ABCB1, positively regulates BR signaling PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0016887 ATP hydrolysis activity | IEA GO_REF:0000120 | ACCEPT | Summary: ATP hydrolysis activity of the ABC transporter nucleotide-binding domains. Reason: Correct; experimentally confirmed and stimulated by bioactive brassinosteroids. Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0042626 ATPase-coupled transmembrane transporter activity | IBA GO_REF:0000033 | MODIFY | Summary: ATPase-coupled transmembrane transporter activity of the ABCB/MDR family; ABCB19 is itself a donor. Reason: The two transmembrane and two nucleotide-binding domains and ATP-dependent transport support the more specific ABC-type transporter activity already represented in this review. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN000657189 SUPPORTS TRANSFER The actual PTHR43394 PAINT table supports this broad ancestral membrane/transport property. ABCB19 is legitimately among the experimental seeds. The target-specific replacement refines a true claim; it does not diagnose a faulty ancestral assertion or circular support. Proposed replacements: ABC-type transporter activity Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0043481 anthocyanin accumulation in tissues in response to UV light | IEA GO_REF:0000117 | UNDECIDED | Summary: UV-specific anthocyanin involvement remains unresolved despite established pigment responses to other wavelengths. Reason: Full PMID:15908594 Fig.3C now resolves the cited assay: anthocyanin was measured after continuous far-red or blue light, and Methods specifies far-red/red/blue LEDs. The UV-A mention describes photoreceptors in the introduction, not a target UV experiment. GO:0043481 requires a UV stimulus. Other reviewed ABCB19 evidence establishes auxin/BR transport and blue-light-dependent physiology but does not independently resolve the UV-specific pigment response. A genuine pigment phenotype under other wavelengths neither establishes nor contradicts UV involvement; retain UNDECIDED for the biological claim, without treating this source limitation as evidence of absence. Supporting Evidence: file:publications/url_https___pmc.ncbi.nlm.nih.gov_articles_PMC1150410_.md 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: UV-specific anthocyanin involvement remains unresolved despite established pigment responses to other wavelengths. Reason: Full PMID:15908594 Fig.3C now resolves the cited assay: anthocyanin was measured after continuous far-red or blue light, and Methods specifies far-red/red/blue LEDs. The UV-A mention describes photoreceptors in the introduction, not a target UV experiment. GO:0043481 requires a UV stimulus. Other reviewed ABCB19 evidence establishes auxin/BR transport and blue-light-dependent physiology but does not independently resolve the UV-specific pigment response. A genuine pigment phenotype under other wavelengths neither establishes nor contradicts UV involvement; retain UNDECIDED for the biological claim, without treating this source limitation as evidence of absence. Supporting Evidence: file:publications/url_https___pmc.ncbi.nlm.nih.gov_articles_PMC1150410_.md 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: ABCB19 contributes with ABCB1 to the auxin-distribution context of male gametophyte development. Reason: Full PMID:35512423 Fig.5 tests abcb1 abcb19 as well as twd1: the double mutant has reduced pollen number and viability and abnormal nuclei. This supports a contextual reproductive contribution of the transporters, not exclusive ABCB19 necessity or a direct pollen-mitosis enzyme. Failed cell plates/callose aggregation are TWD1-specific and are not assigned to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md both pollen viability and pollen number were significantly reduced in the tw1 and the abcb1abcb19 double mutant but not in investigated pin mutants |
| GO:0048364 root development | IMP PMID:17557805 Separating the roles of acropetal and basipetal auxin transp... | KEEP AS NON CORE | Summary: mdr1 roots grow with exaggerated waving/curvature. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native mdr1 mutations reduce root acropetal auxin transport and alter straight growth and auxin distribution. The primary study reports normal reorientation gravitropism in its tested background; this root-development role is retained without making all gravitropic phenotypes universal. Supporting Evidence: PMID:17557805 Vertically grown mdr1 roots produced positive and negative curvatures threefold greater than the wild type |
| GO:0048439 flower morphogenesis | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB19-mediated auxin distribution contributes to late stamen filament growth and flower organization. Reason: The full primary study localizes ABCB19βGFP to filament epidermis/provasculature during rapid late growth and measures reduced filament cell elongation in abcb1 abcb19. Retain this contextual morphogenetic contribution without assigning the TWD1-specific change in stamen number, nectary phenotype or early anther dehiscence to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0048443 stamen development | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB19-mediated auxin distribution contributes to late stamen filament growth and flower organization. Reason: The full primary study localizes ABCB19βGFP to filament epidermis/provasculature during rapid late growth and measures reduced filament cell elongation in abcb1 abcb19. Retain this contextual morphogenetic contribution without assigning the TWD1-specific change in stamen number, nectary phenotype or early anther dehiscence to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0048443 stamen development | IGI PMID:18628351 Auxin regulates Arabidopsis anther dehiscence, pollen matura... | KEEP AS NON CORE | Summary: Auxin transport (ABCB1/ABCB19) contributes to preanthesis filament elongation. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: The source distinguishes auxin-dependent anther/pollen timing from the contribution of transport to preanthesis filament elongation. Retain the stamen-development claim without extending receptor-mediated pollen phenotypes to ABCB19 alone. Supporting Evidence: PMID:18628351 auxin transport contributes to the independent regulation of preanthesis filament elongation |
| GO:0048443 stamen development | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB19-mediated auxin distribution contributes to late stamen filament growth and flower organization. Reason: The full primary study localizes ABCB19βGFP to filament epidermis/provasculature during rapid late growth and measures reduced filament cell elongation in abcb1 abcb19. Retain this contextual morphogenetic contribution without assigning the TWD1-specific change in stamen number, nectary phenotype or early anther dehiscence to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0048461 flower structural organization | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB19-mediated auxin distribution contributes to late stamen filament growth and flower organization. Reason: The full primary study localizes ABCB19βGFP to filament epidermis/provasculature during rapid late growth and measures reduced filament cell elongation in abcb1 abcb19. Retain this contextual morphogenetic contribution without assigning the TWD1-specific change in stamen number, nectary phenotype or early anther dehiscence to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0048461 flower structural organization | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB19-mediated auxin distribution contributes to late stamen filament growth and flower organization. Reason: The full primary study localizes ABCB19βGFP to filament epidermis/provasculature during rapid late growth and measures reduced filament cell elongation in abcb1 abcb19. Retain this contextual morphogenetic contribution without assigning the TWD1-specific change in stamen number, nectary phenotype or early anther dehiscence to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0048527 lateral root development | IMP PMID:17557807 Mutations in Arabidopsis multidrug resistance-like ABC trans... | KEEP AS NON CORE | Summary: Reduced acropetal transport in mdr1 lateral roots slows their growth. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native mdr1 mutants show arrested or slower lateral-root elongation and reduced auxin delivery; auxin rescues the elongation defect. The transporter contributes to the developmental process through local auxin supply, a precise contextual role outside its core reaction. Supporting Evidence: PMID:17557807 impaired acropetal auxin transport due to mutation of the MDR1 gene caused 21% of nascent lateral roots to arrest their growth |
| GO:0051510 regulation of unidimensional cell growth | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB19-mediated auxin distribution contributes to late stamen filament growth and flower organization. Reason: The full primary study localizes ABCB19βGFP to filament epidermis/provasculature during rapid late growth and measures reduced filament cell elongation in abcb1 abcb19. Retain this contextual morphogenetic contribution without assigning the TWD1-specific change in stamen number, nectary phenotype or early anther dehiscence to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0051510 regulation of unidimensional cell growth | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | KEEP AS NON CORE | Summary: ABCB19-mediated auxin distribution contributes to late stamen filament growth and flower organization. Reason: The full primary study localizes ABCB19βGFP to filament epidermis/provasculature during rapid late growth and measures reduced filament cell elongation in abcb1 abcb19. Retain this contextual morphogenetic contribution without assigning the TWD1-specific change in stamen number, nectary phenotype or early anther dehiscence to ABCB19. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0055085 transmembrane transport | IBA GO_REF:0000033 | MODIFY | Summary: Transmembrane transport. Reason: Direct cellular IAA export supports the specific auxin-export process. ABCB19 also transports brassinosteroids, retained separately in its core functions; refinement to this established process does not imply auxin-only substrate specificity. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN000657189 SUPPORTS TRANSFER The actual PTHR43394 PAINT table supports this broad ancestral membrane/transport property. ABCB19 is legitimately among the experimental seeds. The target-specific replacement refines a true claim; it does not diagnose a faulty ancestral assertion or circular support. Proposed replacements: auxin export across the plasma membrane Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0055085 transmembrane transport | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | MODIFY | Summary: Transport of brassinosteroids by ABCB19 in transport assays. Reason: Direct cellular IAA export supports the specific auxin-export process. ABCB19 also transports brassinosteroids, retained separately in its core functions; refinement to this established process does not imply auxin-only substrate specificity. Proposed replacements: auxin export across the plasma membrane Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0055085 transmembrane transport | IEA GO_REF:0000002 | MODIFY | Summary: Transmembrane transport from InterPro. Reason: Direct cellular IAA export supports the specific auxin-export process. ABCB19 also transports brassinosteroids, retained separately in its core functions; refinement to this established process does not imply auxin-only substrate specificity. Proposed replacements: auxin export across the plasma membrane Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0060772 leaf phyllotactic patterning | IMP PMID:32855213 An ATP-Binding Cassette Transporter, ABCB19, Regulates Leaf ... | MARK AS OVER ANNOTATED | Summary: The abcb19 phenotype described is upright petiole angle (leaf position/hyponasty) and wavy leaf blades. Leaf phyllotactic patterning refers to the arrangement of leaves around the stem, which the paper does not address. Reason: The full text describes petiole angle and leaf flattening, not phyllotaxis; the term over-interprets "leaf position". Supporting Evidence: PMID:32855213 abcb19 displays upright petiole angles that remain unchanged in response to red and blue light |
| GO:0060918 auxin transport | IMP PMID:23560110 The ATP-binding cassette transporter ABCB19 regulates postem... | ACCEPT | Summary: Auxin transport by ABCB19 underlies its organ-boundary role. Reason: Correct process. Supporting Evidence: PMID:23560110 these results reveal a new aspect of auxin transporter ABCB19 function |
| GO:0090627 plant epidermal cell differentiation | IEA GO_REF:0000117 | MARK AS OVER ANNOTATED | Summary: The stamen study measures growth of existing epidermal cells rather than acquisition of epidermal cell identity. Reason: GO:0090627 requires a relatively unspecialized cell to acquire specialized epidermal features. Full PMID:35512423 measures filament epidermal cell dimensions, elongation and ABCB19βGFP localization; these establish growth of epidermal cells, not a cell-fate or epidermal-differentiation step. The supported growth/stamen roles remain retained separately. This is a process-specific overinterpretation, not denial of the native phenotype. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0090627 plant epidermal cell differentiation | IMP PMID:35512423 Arabidopsis TWISTED DWARF1 regulates stamen elongation by di... | MARK AS OVER ANNOTATED | Summary: The stamen study measures growth of existing epidermal cells rather than acquisition of epidermal cell identity. Reason: GO:0090627 requires a relatively unspecialized cell to acquire specialized epidermal features. Full PMID:35512423 measures filament epidermal cell dimensions, elongation and ABCB19βGFP localization; these establish growth of epidermal cells, not a cell-fate or epidermal-differentiation step. The supported growth/stamen roles remain retained separately. This is a process-specific overinterpretation, not denial of the native phenotype. Supporting Evidence: file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md 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 compared with the wild type (194.8 Β± 2.9 ΞΌm) file:publications/url_https___oup.silverchair-cdn.com_article-minimal_6581225.md ABCB19βGFP expression was very strong in stamen filaments at flower stage 12 and was localized in both epidermal and provascular cells |
| GO:0090691 formation of plant organ boundary | IMP PMID:23560110 The ATP-binding cassette transporter ABCB19 regulates postem... | KEEP AS NON CORE | Summary: abcb19-5 shows stem-cauline leaf and stem-pedicel fusion (organ boundary) defects. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native abcb19-5 has stemβleaf and stemβpedicel fusion, changed boundary auxin and reduced boundary-gene expression. Transport contributes to organ separation; ABCB19 is not a boundary-gene transcription factor. Supporting Evidence: PMID:23560110 We identified a new abcb19 allele, abcb19-5, which showed stem-cauline leaf and stem-pedicel fusion defects. |
| GO:0140359 ABC-type transporter activity | IDA PMID:38513023 Structure and function of the Arabidopsis ABC transporter AB... | ACCEPT | Summary: ABCB19 is an ATP-driven ABC exporter of brassinosteroids (structure solved with bound BR). Reason: Core MF. Supporting Evidence: PMID:38513023 a member of the ATP-binding cassette (ABC) transporter superfamily, ABCB19, functions as a brassinosteroid exporter PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:0140359 ABC-type transporter activity | IEA GO_REF:0000002 | ACCEPT | Summary: ABC-type transporter activity from InterPro. Reason: Core MF: ABCB19 is a full-size ABCB exporter. Supporting Evidence: PMID:38513023 Bioactive brassinosteroids are potent activators of ABCB19 ATP hydrolysis activity, and transport assays showed that ABCB19 transports brassinosteroids. |
| GO:1900459 positive regulation of brassinosteroid mediated signaling pathway | IEA GO_REF:0000117 | KEEP AS NON CORE | Summary: ABCB19 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 ABCB19, nor resolve the BR-versus-auxin contribution to every growth phenotype. Supporting Evidence: PMID:39497419 ABCB19 functions as a BR exporter and, together with its close homolog ABCB1, positively regulates BR signaling |
| 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: ABCB19 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 ABCB19, nor resolve the BR-versus-auxin contribution to every growth phenotype. Supporting Evidence: 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: ABCB19 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 ABCB19, nor resolve the BR-versus-auxin contribution to every growth phenotype. Supporting Evidence: PMID:39497419 ABCB19 functions as a BR exporter and, together with its close homolog ABCB1, positively regulates BR signaling |
| GO:1901371 regulation of leaf morphogenesis | IMP PMID:32855213 An ATP-Binding Cassette Transporter, ABCB19, Regulates Leaf ... | KEEP AS NON CORE | Summary: abcb19 rosette leaves are irregularly wavy. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native abcb19 mutants have altered petiole angle and blue-light-dependent leaf flattening, associated with altered auxin transport/distribution. Retain this contextual response, distinguished from the placement of new leaf primordia. Supporting Evidence: PMID:32855213 abcb19 mutants develop irregularly wavy rosette leaves that are less sensitive to blue light-mediated leaf flattening |
| GO:1902347 response to strigolactone | IMP PMID:30865619 Connective auxin transport contributes to strigolactone-medi... | KEEP AS NON CORE | Summary: Loss of ABCB19 partially suppresses the branching of strigolactone mutants. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native genetic combinations implicate ABCB19 in auxin loading at axillary bud apices and strigolactone-dependent shoot-branching control. This is a transport-mediated developmental contribution, not strigolactone perception. Supporting Evidence: PMID:30865619 Because loss of ABCB19 in strigolactone mutant backgrounds reduces branching in intact plants, we wondered whether abcb19 mutants were strigolactone resistant. |
| GO:2000032 regulation of secondary shoot formation | IMP PMID:30865619 Connective auxin transport contributes to strigolactone-medi... | KEEP AS NON CORE | Summary: abcb19 reduces shoot branching in max2/max4 backgrounds. The phenotype reflects altered auxin (or brassinosteroid) distribution caused by loss of ABCB19 transport activity. Reason: Native genetic combinations implicate ABCB19 in auxin loading at axillary bud apices and strigolactone-dependent shoot-branching control. This is a transport-mediated developmental contribution, not strigolactone perception. Supporting Evidence: PMID:30865619 loss of ABCB19 reduced the levels of shoot branching in both |
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Download this section (compressed HTML)Q: How does a single ABCB19 binding cavity accommodate both IAA and brassinosteroids, and is there competition between the two substrates in planta?
Suggested experts: ABC transporter structural biologists, Plant hormone transport researchers
Q: A GO process term for brassinosteroid export/transport does not exist; should one be requested so that ABCB19/ABCB1 BR export can be annotated precisely?
Suggested experts: GO editors
Experiment: Measure brassinolide-stimulated ATPase and IAA transport of purified ABCB19 (with TWD1) in proteoliposomes in the presence of increasing concentrations of the other substrate, and test binding-pocket mutants.
Hypothesis: IAA and brassinolide compete for the same ABCB19 binding site.
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