中国科学技术大学孙林峰课题组近日取得一项新成果。他们的最新研究提出了拟南芥AUX1介导的生长素内流的结构研究。这一研究成果于2025年5月15日发表在国际顶尖学术期刊《细胞》上。

研究了拟南芥中AUX1介导的生长素摄取。利用低温电子显微镜（cryo-EM），研究小组确定了它在三种状态下的结构：生长素未结合状态、生长素结合状态和竞争抑制剂3-氯-4-羟基苯基乙酸（CHPAA）结合状态。所有结构都采用向内的构象。在生长素结合结构中，吲哚-3-乙酸（IAA）主要通过与其羧基的氢键与生长素1配合。通过体外和植物分析验证了关键残基在IAA结合中的功能作用。CHPAA与IAA结合在同一个位点上。这些发现促进了他们对植物生长素转运的理解。

据了解，生长素在协调植物生长发育的各个方面以及调节对环境信号的反应中起着至关重要的作用。生长素的时空分布不对称，产生局部梯度模式，受细胞生长素内流和外排调控。生长素1/LIKE-AUX1 （AUX1/LAX）家族转运蛋白被认为是生长素内流的主要载体。

附：英文原文

Title: Structural insights into auxin influx mediated by the Arabidopsis AUX1

Author: Zhisen Yang, Hong Wei, Yulin Gan, Huihui Liu, Yang Cao, Huihui An, Xiuzheng Que, Yongxiang Gao, Lizhe Zhu, Shutang Tan, Xin Liu, Linfeng Sun

Issue&Volume: 2025-05-15

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.

DOI: 10.1016/j.cell.2025.04.028

Source: https://www.cell.com/cell/abstract/S0092-8674(25)00463-5