9JDS

Structure of the auxin importer AUX1 in Arabidopsis thaliana in the IAA-bound state

Summary for 9JDS

• Entry DOI: 10.2210/pdb9jds/pdb
• EMDB information: 61398
• Descriptor: Auxin transporter protein 1, 1H-INDOL-3-YLACETIC ACID (3 entities in total)
• Functional Keywords: auxin, importer, aux1, membrane protein
• Biological source: Arabidopsis thaliana (thale cress)
• Total number of polymer chains: 1
• Total formula weight: 54280.70

Authors

Sun, L.,Liu, X.,Wei, H.,Yang, Z. (deposition date: 2024-09-01, release date: 2025-06-11, Last modification date: 2026-06-24)

Primary citation

Yang, Z.,Wei, H.,Gan, Y.,Liu, H.,Cao, Y.,An, H.,Que, X.,Gao, Y.,Zhu, L.,Tan, S.,Liu, X.,Sun, L.
Structural insights into auxin influx mediated by the Arabidopsis AUX1.
Cell, 188:3960-3973.e15, 2025

PubMed Abstract: Auxin is crucial in orchestrating diverse aspects of plant growth and development and modulating responses to environmental signals. The asymmetric spatiotemporal distribution of auxin generates local gradient patterns, which are regulated by both cellular auxin influx and efflux. The AUXIN1/LIKE-AUX1 (AUX1/LAX) family transporters have been identified as major auxin influx carriers. Here, we characterize the auxin uptake mediated by AUX1 from Arabidopsis thaliana. Using cryoelectron microscopy (cryo-EM), we determine its structure in three states: the auxin-unbound, the auxin-bound, and the competitive inhibitor, 3-chloro-4-hydroxyphenylacetic acid (CHPAA)-bound state. All structures adopt an inward-facing conformation. In the auxin-bound structure, indole-3-acetic acid (IAA) is coordinated to AUX1 primarily through hydrogen bonds with its carboxyl group. The functional roles of key residues in IAA binding are validated by in vitro and in planta analyses. CHPAA binds to the same site as IAA. These findings advance our understanding of auxin transport in plants.

PubMed: 40378849
DOI: 10.1016/j.cell.2025.04.028

Experimental method

ELECTRON MICROSCOPY (3.4 Å)