ROOT HAIR DEFECTIVE3 Family of Dynamin-Like GTPases Mediates Homotypic Endoplasmic Reticulum Fusion and Is Essential for Arabidopsis Development
ROOT HAIR DEFECTIVE3 Family of Dynamin-Like GTPases Mediates Homotypic Endoplasmic Reticulum Fusion and Is Essential for Arabidopsis Development
复制标题
根毛缺陷 3 动力蛋白样 GTP 酶家族介导同型内质网融合，对拟南芥发育至关重要
DOI：
10.1104/pp.113.224501
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发表时间：
2013-10-01
期刊：
影响因子：
7.4
通讯作者：
Hu, Junjie
中科院分区：
文献类型：
--
作者：
Zhang, Miao;Wu, Fuyun;Hu, Junjie
在所有真核细胞中，内质网（ER）形成管状网络，其产生需要内质网膜的融合。在拟南芥（Arabidopsis thaliana）中，膜结合的GTPase ROOT HAIR DEFECTIVE3 （RHD3）是介导内质网融合的潜在候选者。此外，拟南芥存在两种组织特异性的RHD3亚型，即RHD3样蛋白（RL），其功能尚不清楚。在这里，我们发现RHD3的一个空等位基因RHD3 -8导致生长缺陷和根毛缩短。点突变体rhd3-1表现出比零突变体更严重的生长表型，可能是因为它对RL蛋白施加了显性负向作用。遗传分析表明，RHD3和RL1的双缺失是致命的，RHD3和rl2植株不产生活花粉，表明RL蛋白对RHD3是冗余的。RHD3家族蛋白可以取代酵母（Saccharomyces cerevisiae）中RHD3的同源物Sey1p，维持内质网形态，并且在体内和体外都能够融合膜。我们的研究结果表明，RHD3蛋白介导内质网融合，对植物发育至关重要，并且管状内质网的形成具有普遍的生理意义。
In all eukaryotic cells, the endoplasmic reticulum (ER) forms a tubular network whose generation requires the fusion of ER membranes. In Arabidopsis (Arabidopsis thaliana), the membrane-bound GTPase ROOT HAIR DEFECTIVE3 (RHD3) is a potential candidate to mediate ER fusion. In addition, Arabidopsis has two tissue-specific isoforms of RHD3, namely RHD3-like (RL) proteins, and their function is not clear. Here, we show that a null allele of RHD3, rhd3-8, causes growth defects and shortened root hairs. A point mutant, rhd3-1, exhibits a more severe growth phenotype than the null mutant, likely because it exerts a dominant-negative effect on the RL proteins. Genetic analysis reveals that the double deletion of RHD3 and RL1 is lethal and that the rhd3 rl2 plants produce no viable pollen, suggesting that the RL proteins are redundant to RHD3. RHD3 family proteins can replace Sey1p, the homolog of RHD3 in yeast (Saccharomyces cerevisiae), in the maintenance of ER morphology, and they are able to fuse membranes both in vivo and in vitro. Our results suggest that RHD3 proteins mediate ER fusion and are essential for plant development and that the formation of the tubular ER network is of general physiological significance.