Abstract
Brassinosteroids (BRs) are steroidal phytohormones indispensable for plant growth, development, and responses to environmental stresses. The export of bioactive BRs to the apoplast is essential for BR signaling initiation, which requires binding of a BR molecule to the extracellular domains of the plasma membrane-localized receptor complex. We have previously shown that the Arabidopsis thaliana ATP-binding cassette (ABC) transporter ABCB19 functions as a BR exporter and, together with its close homolog ABCB1, positively regulates BR signaling. Here, we demonstrate that ABCB1 is another BR transporter. The ATP hydrolysis activity of ABCB1 can be stimulated by bioactive BRs, and its transport activity was confirmed in proteoliposomes and protoplasts. Structures of ABCB1 were determined in substrate-unbound (apo), brassinolide (BL)-bound, and ATP plus BL-bound states. In the BL-bound structure, BL is bound to the hydrophobic cavity formed by the transmembrane domain and triggers local conformational changes. Together, our data provide additional insights into ABC transporter-mediated BR export.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by-nc-nd. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 5
Claim · model-written summary
ABCB1 functions as a brassinosteroid transporter.
- Taxon
- Arabidopsis
Arabidopsist0 - Gene
- ABCB1e0
- Outcome
- BR transportere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Here, we demonstrate that ABCB1 is another BR transporter.”
t0“Arabidopsis”
Claim · model-written summary
Bioactive brassinosteroids stimulate ATP hydrolysis by ABCB1.
- Taxon
- ArabidopsisArabidopsist0
- Treatment
- bioactive BRse0
- Gene
- ABCB1e0
- Outcome
- ATP hydrolysis activitye0
- Direction
- stimulatede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The ATP hydrolysis activity of ABCB1 can be stimulated by bioactive BRs”
t0“Arabidopsis”
Claim · model-written summary
ABCB1 transport activity was confirmed in proteoliposomes and protoplasts.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- ABCB1t0
- Outcome
- transport activitye0
- Setting
- proteoliposomes and protoplastse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“its transport activity was confirmed in proteoliposomes and protoplasts”
t0“Arabidopsis ABC transporter ABCB1”
Claim · model-written summary
Structures of ABCB1 were determined in apo, BL-bound, and ATP plus BL-bound states.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- ABCB1e0
- Outcome
- Structures of ABCB1e0
- Comparator
- substrate-unbound (apo), brassinolide (BL)-bound, and ATP plus BL-bound statese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Structures of ABCB1 were determined in substrate-unbound (apo), brassinolide (BL)-bound, and ATP plus BL-bound states.”
t0“Arabidopsis”
Claim · model-written summary
BL binds the hydrophobic transmembrane cavity of ABCB1 and triggers local conformational changes.
- Taxon
- ArabidopsisArabidopsist0
- Gene
- ABCB1t0
- Compound
- BLe0
- Outcome
- local conformational changese0
- Qualifier
- hydrophobic cavity formed by the transmembrane domaine0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“BL is bound to the hydrophobic cavity formed by the transmembrane domain and triggers local conformational changes”
t0“Arabidopsis ABC transporter ABCB1”
The same questions in other papers
class · molecular: metabolites · ArabidopsisPositive and negative results
6 papers in the same direction as this paper · 5 in the opposite direction
- positive
- no effect
- no effect
8 papers more in this group
See all 12 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.