Arabidopsis RAD23B regulates pollen development by mediating KRP1 degradation

First author: Lan Li; Affiliations: Hunan University (湖南大学): Changsha, China

Corresponding author: Xuanming Liu

The ubiquitin (Ub)/26S proteasome system (UPS) plays a key role in plant growth, development, and survival by directing the turnover of numerous regulatory proteins. In UPS, ubiquitin-like (UBL) and ubiquitin-associated (UBA) domains function as hubs for ubiquitin-mediated protein degradation. RADIATION SENSITIVE23 (RAD23), which was identified as a UBL/UBA protein, contributed to cell cycle progression, stress response, ER proteolysis, and DNA repair. Here, we report pollen is arrested at the microspore stage in a null rad23b mutant. We demonstrated that RAD23B can directly interact with KIP-RELATED PROTEIN 1 (KRP1) through its UBL-UBA domains. In addition, overexpression plants of KRP1 resulted in pollen development defects, a phenotype similar to the rad23b mutant. Finally, RAD23B was found to promote the degradation of KRP1 in vivo, which was accumulated following treatment with MG132. In summary, these results indicate the important role of RAD23B in pollen development by controlling turnover of a key cell cycle protein, KRP1.

泛素/26S蛋白酶体系统（UPS）在植物的生长和发育过程中扮演着非常重要的作用，主要作用于多个调控蛋白的周转。在UPS中，类泛素UBL和泛素相关UBA结构域作为功能核心，作用于泛素介导的蛋白降解。RAD23是一个UBL/UBA蛋白，作用于细胞周期进程、胁迫响应、ER蛋白水解以及DNA修复。本文中，作者报道了rad23b突变体的花粉发育会停滞于小孢子阶段。作者发现RAD23B能够通过其自身的UBL-UBA结构域，直接与KRP1互作。另外，过表达KRP1会导致花粉发育存在缺陷，且缺陷的表型与rad23b突变体的花粉缺陷表型类似。最终，作者通过体内试验显示RAD23B能够促进KRP1的降解，而后者在使用蛋白酶体抑制剂MG132处理后会在体内积累。综上，作者的研究揭示了RAD23B通过控制一个细胞周期关键蛋白KRP1的周转，从而在花粉发育过程中发挥重要的作用。

通讯：刘选明 (https://zhxy.csuft.edu.cn/szdw/jsml/201006/t20100601_34193.html)

个人简介：1986年，湖南师范大学，学士；1989年，湖南农业大学，硕士；1995年，湖南农业大学，博士。

研究方向：植物生长发育与遗传调控，植物基因挖掘、调控网络与响应环境分子机制，植物分子育种与新品种选育。

doi: https://doi.org/10.1093/jxb/eraa167

Journal: Journal of Experimental Botany

Published date: April 03, 2020

p.s. 花粉发育相关文章链接：

Plant Biotechnol J：玉米STK基因参与花粉发育的分子调控

PLoS Genetics：拟南芥非光合质体中的脂肪酸合成作用于花粉发育

PLoS Genetics：孢子体产生的生长素作用于配子体发育

the plant journal：水稻花药发育基因共表达网络

Plant Cell：拟南芥三沟型花粉形成机制