Arabidopsis RHD3 mediates the generation of the tubular ER network and is required for Golgi distribution and motility in plant cells
Arabidopsis RHD3 mediates the generation of the tubular ER network and is required for Golgi distribution and motility in plant cells
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DOI：
10.1242/jcs.084624
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发表时间：
2011-07-01
影响因子：
4
通讯作者：
Zheng, Huanquan
中科院分区：
文献类型：
--
作者：
Chen, Jun;Stefano, Giovanni;Zheng, Huanquan
在植物细胞中，内质网（ER）和高尔基体形成一个独特的系统，其中单个高尔基体堆叠是能动的，并与下面的内质网小管密切相关。拟南芥有三种RHD 3（根毛缺陷3）亚型，它们类似于参与ER小管成形的哺乳动物atlastin GTPases。我们在拟南芥和烟草中使用活细胞成像、遗传互补、分裂泛素测定和蛋白质印迹分析来表明RHD 3介导管状ER网络的产生，并且是根和叶表皮细胞中高尔基体堆叠的分布和运动所必需的。我们建立了RHD 3在内质网斑点形成同型相互作用。此外，RHD 3对管状ER的活性与高尔基体堆叠的细胞分布和运动性特别相关，因为ER到高尔基体以及高尔基体到质膜的转运不受保守GDP/GTP基序中的RHD 3突变的影响。我们发现了一个可能的部分冗余内的RHD 3异构体在拟南芥。然而，酵母Sey 1 p，一个功能性的atlastin同系物，和RHD 3是不可互换的补充各自的功能丧失突变体，这表明控制内质网管状形态的分子机制可能不完全保守的真核细胞谱系。
In plant cells, the endoplasmic reticulum (ER) and Golgi apparatus form a unique system in which single Golgi stacks are motile and in close association with the underlying ER tubules. Arabidopsis has three RHD3 (ROOT HAIR DEFECTIVE 3) isoforms that are analogous to the mammalian atlastin GTPases involved in shaping ER tubules. We used live-cell imaging, genetic complementation, split ubiquitin assays and western blot analyses in Arabidopsis and tobacco to show that RHD3 mediates the generation of the tubular ER network and is required for the distribution and motility of Golgi stacks in root and leaf epidermal cells. We established that RHD3 forms homotypic interactions at ER punctae. In addition, the activity of RHD3 on the tubular ER is specifically correlated with the cellular distribution and motility of Golgi stacks because ER to Golgi as well as Golgi to plasma membrane transport was not affected by RHD3 mutations in the conserved GDP/GTP motifs. We found a possible partial redundancy within the RHD3 isoforms in Arabidopsis. However, yeast Sey1p, a functional atlastin homologue, and RHD3 are not interchangeable in complementing the respective loss-of-function mutants, suggesting that the molecular mechanisms controlling ER tubular morphology might not be entirely conserved among eukaryotic lineages.