26S蛋白酶体调控微管蛋白的降解

26S proteasome regulates the degradation of microtubule

摘要:

为了探究微管蛋白在植物细胞中的降解机制,本文利用微管解聚药物、蛋白酶体抑制剂MG132结合遗传学和分子生物学等体内体外研究技术发现微管蛋白TUA和TUB是通过泛素化/26S蛋白酶体途径降解的,同时在26S蛋白酶体调节亚基RPN10突变体 rpn 10-1的植株中,TUA的降解与野生型相比没有显著差别,但是TUB的降解在突变体中被严重削弱,使得 TUB 在突变体中过量积累.此外,在突变体中分别过量表达TUA和TUB,对转基因植株鉴定表明过量表达TUA促进突变体根的生长而过量表达TUB严重抑制了突变体的生长,说明在突变体中TUA/TUB的比例是失衡的,过量的TUB蛋白对植物的生长是不利的.以上结果表明,26S蛋白酶体可以调控微管蛋白TUA和TUB的降解,蛋白酶体调控亚基RPN10可以通过调控TUB 的稳定性来影响植物的生长和发育.

Abstract:

To analyze the degradation mechanism of microtubules protein in the plant cell, we used anti-MT, proteasome inhibitor MG132 combining the in vivo and in vitro techniques of genetics and plant molecular biology to reveal that the degradation of TUA and TUB was mediated by the ubiquitin/26S proteasome. Our results indicated that in the loss of function mutant rpn 10-1 of regulatory subunit RPN10 of the 26S proteasome, the degradation of TUB was impaired while that of TUA was not affected, as compared with wild type plants. Meanwhile, overexpression of TUA in mutant rpn 10-1 increased the root length while overexpression of TUB inhibited root elongation of rpn 10-1and the ratio of TUA to TUB were an imbalance in mutant rpn 10-1, which suppressed the root growth. Together, our results indicated that 26S proteasome is required for the degradation of tubulins (TUA and TUB) and RPN10 can influence plant growth by regulating protein stability of TUB.