8ZPX

Structure of the wild-type Arabidopsis ABCB1 in the apo state

Summary for 8ZPX

• Entry DOI: 10.2210/pdb8zpx/pdb
• EMDB information: 60366
• Descriptor: ABC transporter B family member 1 (1 entity in total)
• Functional Keywords: abc transporter, wild-type, apo state, transport protein
• Biological source: Arabidopsis thaliana (thale cress)
• Total number of polymer chains: 1
• Total formula weight: 140729.14

Authors

Ying, W.,Wei, H.,Liu, X.,Sun, L. (deposition date: 2024-05-31, release date: 2025-03-12)

Primary citation

Wei, H.,Zhu, H.,Ying, W.,Janssens, H.,Kvasnica, M.,Winne, J.M.,Gao, Y.,Friml, J.,Ma, Q.,Tan, S.,Liu, X.,Russinova, E.,Sun, L.
Structural insights into brassinosteroid export mediated by the Arabidopsis ABC transporter ABCB1.
Plant Commun., 6:101181-101181, 2025

PubMed 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.

PubMed: 39497419
DOI: 10.1016/j.xplc.2024.101181

Experimental method

ELECTRON MICROSCOPY (3.5 Å)