A key residue of the extracellular gate provides quality control contributing to ABCG substrate specificity
For G-type ATP-binding cassette (ABC) transporters, a hydrophobic "di-leucine motif" as part of a hydrophobic extracellular gate has been described to separate a large substrate-binding cavity from a smaller upper cavity and proposed to act as a valve controlling drug extrusion. Here, we show that an L704F mutation in the hydrophobic extracellular gate of Arabidopsis ABCG36/PDR8/PEN3 uncouples the export of the auxin precursor indole-3-butyric acid (IBA) from that of the defense compound camalexin (CLX). Molecular dynamics simulations reveal increased free energy for CLX translocation in ABCG36<sup>L704F</sup> and reduced CLX contacts within the binding pocket proximal to the extracellular gate region. Mutation L704Y enables export of structurally related non-ABCG36 substrates, IAA, and indole, indicating allosteric communication between the extracellular gate and distant transport pathway regions. An evolutionary analysis identifies L704 as a Brassicaceae family-specific key residue of the extracellular gate that controls the identity of chemically similar substrates. In summary, our work supports the conclusion that L704 is a key residue of the extracellular gate that provides a final quality control contributing to ABCG substrate specificity, allowing for balance of growth-defense trade-offs.
Authors
- Odalys Torres (ORCID: https://orcid.org/0000-0002-7263-6425)
- Noel Ferro (ORCID: https://orcid.org/0000-0003-3121-2084)
- Joanna Banasiak (ORCID: https://orcid.org/0000-0002-2834-7116)
- Jörg Ziegler (ORCID: https://orcid.org/0000-0001-6757-1164)
- Tamás Hegedűs (ORCID: https://orcid.org/0000-0002-5195-749X)
- Konrad Pakuła (ORCID: https://orcid.org/0000-0003-4189-1981)
- Francesca Romana Iacobini (ORCID: https://orcid.org/0000-0001-8339-6909)
- Sabine Rosahl (ORCID: https://orcid.org/0000-0002-7300-5596)
- Alexandra Siffert (ORCID: https://orcid.org/0000-0002-4894-5172)
- Jian Xia (ORCID: https://orcid.org/0000-0001-9294-7960)
- Michał Jasiński (ORCID: https://orcid.org/0000-0003-0904-5873)
- Markus Geisler (ORCID: https://orcid.org/0000-0002-6641-5810)
Institutions
- Semmelweis University (HU)
- University of Fribourg (CH)
- Corvinus University of Budapest (HU)
- Hess (United States) (US)
- University of Zurich (CH)
- Friedrich-Ebert-Stiftung e.V. (DE)
- Leibniz Institute of Plant Biochemistry (DE)
- Institute of Bioorganic Chemistry, Polish Academy of Sciences (PL)
- University of Life Sciences in Poznań (PL)
- Martin Luther University Halle-Wittenberg (DE)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-05-05
- DOI
- https://doi.org/10.1038/s41467-025-59518-3
- Citations
- 1
- Primary Topic
- Drug Transport and Resistance Mechanisms
- Type
- article
- Field-Weighted Citation Impact
- 1.05
Funders
- Deutsche Forschungsgemeinschaft
- China Scholarship Council
- Université de Fribourg
- Nemzeti Kutatási Fejlesztési és Innovációs Hivatal
- National Research, Development and Innovation Office