2. Academic Validation
  3. Structural insights into brassinosteroid export mediated by the Arabidopsis ABC transporter ABCB1

Structural insights into brassinosteroid export mediated by the Arabidopsis ABC transporter ABCB1

  • Plant Commun. 2024 Nov 4:101181. doi: 10.1016/j.xplc.2024.101181.
Hong Wei 1,  Heyuan Zhu 2,  Wei Ying 1,  Hilde Janssens 3,  Miroslav Kvasnica 4,  Johan M Winne 3,  Yongxiang Gao 1,  Jiří Friml 5,  Qian Ma 2,  Shutang Tan 6,  Xin Liu 6,  Eugenia Russinova 7,  Linfeng Sun 6
Affiliations

Affiliations

  • 1 MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027 Hefei, China.
  • 2 University Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium.
  • 3 Department of Organic and Macromolecular Chemistry, Ghent University, 9000 Ghent, Belgium.
  • 4 Laboratory of Growth Regulators, Institute of Experimental Botany, The Czech Academy of Sciences and Palacký University, 77900 Olomouc, Czech Republic.
  • 5 Institute of Science and Technology Austria (ISTA), Am Campus 1, 3400 Klosterneuburg, Austria.
  • 6 MOE Key Laboratory for Membraneless Organelles and Cellular Dynamics, Hefei National Research Center for Physical Sciences at the Microscale, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, 230027 Hefei, China. Electronic address: sttan@ustc.edu.cn.
  • 7 University Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Center for Plant Systems Biology, VIB, 9052 Ghent, Belgium. Electronic address: sttan@ustc.edu.cn.
PMID: 39497419 DOI: 10.1016/j.xplc.2024.101181
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 signalling initiation, which requires binding of 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 homologue, ABCB1, positively regulate BR signalling. Here, we demonstrate that ABCB1 is another BR transporter. The ATP hydrolysis activity of ABCB1 was stimulated by bioactive BRs, and its transport activity was confirmed in proteoliposomes and protoplasts. Structures of ABCB1 in substrate-unbound (apo), Brassinolide (BL)-bound, and ATP plus BL-bound states were determined. In the BL-bound structure, BL was bound to the hydrophobic cavity formed by the transmembrane domain, and triggered local conformational changes. Together, our data provide additional insights into the ABC transporter-mediated BR export.

Keywords

ABCB1; Arabidopsis; Brassinosteroid (BR); signalling; structure; transport.

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