Perinuclear and nuclear envelope localizations of Arabidopsis Ran proteins

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• 作者：Lian Ma ; Zonglie Hong and Zhongming Zhang
• 关键词：Arabidopsis thaliana ; GTPase ; Phragmoplastin ; Nuclear envelope ; Cell division ; Cytokinesis
• 刊名：Plant Cell Reports
• 出版年：2007
• 出版时间：August, 2007
• 年：2007
• 卷：26
• 期：8
• 页码：1373-1382
• 全文大小：398 KB

文摘

Using phragmoplastin-interacting protein 1 (PhrIP1) as bait, we isolated an Arabidopsis cDNA encoding Ran2, a small Ras-like GTP-binding protein. The interaction between PhrIP1 and Ran2 was confirmed by an in vitro protein–protein interaction assay with purified Ran2 and PhrIP1. The plant Ran2 shares high sequence homology, 78 and 86 % at the amino acid level, with human Ran/TC4 and C. elegans Ran, respectively. Our results obtained from enzyme assays and Western blot analysis show that Ran2 has intrinsic GTPase activity and is present in the soluble fraction of Arabidopsis seedling extract. Fluorescent microscopy using anti-Ran2 antibody revealed that the Ran protein is localized in the perinuclear region with the highest concentration at the nuclear envelope. In contrast to its animal counterparts that are present in the nucleoplasm, the Ran protein is absent inside the nucleus. These results suggest that plant Ran proteins may be involved in mediation of nucleocytoplasmic transport and assembly of the nuclear envelope after karyokinesis in plant cells.