Auxin influx carrier protein 1 (AUX1)

Auxin influx carrier protein 1 (AUX1) is a high-affinity transporter responsible for the cellular import of auxin (specifically indole-3-acetic acid, IAA), the primary plant growth hormone[1][3][4][5]. AUX1 belongs to the AUX/LAX family of multi-pass transmembrane proteins and is homologous to amino acid permeases, functioning as a proton-coupled symporter[1][5][3][7]. Its activity is essential for establishing auxin gradients that control a wide range of developmental processes in plants, including root architecture, gravitropic responses, and tissue patterning[5][6]. Mutations in AUX1 lead to aberrant auxin distribution and pronounced morphological defects, especially in root growth and directional responses to gravity. Recent structural studies have resolved the mechanism of substrate recognition and transport, showing that AUX1 recognizes IAA via a set of conserved residues in a classic LeuT-fold transporter structure and is inhibited by certain synthetic molecules (such as 1-NOA and CHPAA)[4]. While AUX1 itself is not a direct target for pharmacological intervention in medicine or agriculture, it is a central model for understanding hormone transport in plants, with indirect implications for crop science and synthetic biology.

Other names

AUX1AUX/LAX family proteinAuxin influx carrier proteinArabidopsis auxin influx carrier AUX1Auxin permease

Competitively inhibit auxin binding and/or transport by occupying the auxin binding pocket Disrupt proton-coupling required for transport[4][3]