Polar recruitment of RLD by LAZY1-like protein during gravity signaling in root branch angle control

First author: Masahiko Furutani; Affiliations: Fujian Agriculture and Forestry University (福建农林大学): Fujian, China

Corresponding author: Miyo Terao Morita

In many plant species, roots maintain specific growth angles relative to the direction of gravity, known as gravitropic set point angles (GSAs). These contribute to the efficient acquisition of water and nutrients. AtLAZY1/LAZY1-LIKE (LZY) genes are involved in GSA control by regulating auxin flow toward the direction of gravity in Arabidopsis. Here, we demonstrate that RCC1-like domain (RLD) proteins, identified as LZY interactors, are essential regulators of polar auxin transport. We show that interaction of the CCL domain of LZY with the BRX domain of RLD is important for the recruitment of RLD from the cytoplasm to the plasma membrane by LZY. A structural analysis reveals the mode of the interaction as an intermolecular β-sheet in addition to the structure of the BRX domain. Our results offer a molecular framework in which gravity signal first emerges as polarized LZY3 localization in gravity-sensing cells, followed by polar RLD1 localization and PIN3 relocalization to modulate auxin flow.

在许多植物中，根维持着相对于重力方向特定角度方向生长，被称为重力设定点角度GSA。这些过程共同作用于植物对于水分和营养的有效获取。拟南芥LZY基因通过调控朝向重力方向的生长素流参与了GSA的控制。本文中，作者的研究揭示了类RCC1结构域蛋白RLD作为LZY的互作因子，对于极性生长素转运调控是必不可少的。作者发现LZY蛋白中的CCL结构域能够与RLD蛋白中的BRX结构域发生互作，并且这对于LZY将RLD从胞质中招募到质膜上是非常重要的。结构分析显示除了BRX结构域的结构之外，相互作用的模式还体现为分子间β-折叠。本文的研究提供了一个分子框架，其中重力信号首先以极性定位于重力感应细胞中的LZY3的方式出现，然后是RLD1的极性定位以及PIN3蛋白的重定位，进而调控生长素流。

通讯：Miyo Terao Morita (https://www.nibb.ac.jp/en/sections/environmental_biology/morita/index.html)

个人简介：1990-1995年，京都大学，博士。

研究方向：重力在高等植物中的分子机制。

doi: https://doi.org/10.1038/s41467-019-13729-7

Journal: Nature Communications

Published date: January 03, 2019