Regulation of cytokinesis by exocyst subunit SEC6 and KEULE in Arabidopsis thaliana.
Regulation of cytokinesis by exocyst subunit SEC6 and KEULE in Arabidopsis thaliana.
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DOI：
10.1093/mp/sst082
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发表时间：
2013-11
期刊：
影响因子：
27.5
通讯作者：
Jiandong Wu;Xiaoyun Tan;Chengyun Wu;Kun Cao;Yan Li;Yiqun Bao
中科院分区：
文献类型：
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作者：
Jiandong Wu;Xiaoyun Tan;Chengyun Wu;Kun Cao;Yan Li;Yiqun Bao
适当的囊泡连接和细胞板上的膜融合是胞质分裂所必需的。囊泡拴系复合体外囊和膜融合调节因子keule在细胞板的形成中都发挥了作用，但其确切机制仍有待进一步研究。在本研究中，利用酵母双杂交(Y-2-H)实验，我们发现SEC6与Keule相互作用，并且这种相互作用需要Keule的一小部分C-末端区域。使用体外下拉实验、免疫沉淀和体内双分子荧光互补(BIFC)显微镜的进一步研究支持了SEC6-keule的直接相互作用。据报道，sec6突变体是雄性配子体致死的；然而，花粉拯救的sec6突变体(PRsec6)在胚胎细胞中表现出胞质分裂缺陷，随后在叶面细胞和保卫细胞中出现胞质分裂缺陷。在转基因拟南芥中，SEC6和Keule蛋白在细胞质分裂过程中共定位于细胞板。此外，在体外，只有SEC6而不是位于细胞板中的其他外囊亚基与Keule相互作用。这些结果表明，SEC6和keule一样在细胞质分裂中起着生理作用，SEC6-keule的相互作用可能是到达囊泡和膜融合机制之间的一种新的分子联系，或者直接调节植物细胞板形成过程中的膜融合。
Proper vesicle tethering and membrane fusion at the cell plate are essential for cytokinesis. Both the vesicle tethering complex exocyst and membrane fusion regulator KEULE were shown to function in cell plate formation, but the exact mechanisms still remain to be explored. In this study, using yeast two-hybrid (Y-2-H) assay, we found that SEC6 interacted with KEULE, and that a small portion of C-terminal region of KEULE was required for the interaction. The direct SEC6-KEULE interaction was supported by further studies using in vitro pull-down assay, immunoprecipitation, and in vivo bimolecular fluorescence complementation (BIFC) microscopy. sec6 mutants were male gametophytic lethal as reported; however, pollen-rescued sec6 mutants (PRsec6) displayed cytokinesis defects in the embryonic cells and later in the leaf pavement cells and the guard cells. SEC6 and KEULE proteins were co-localized to the cell plate during cytokinesis in transgenic Arabidopsis. Furthermore, only SEC6 but not other exocyst subunits located in the cell plate interacted with KEULE in vitro. These results demonstrated that, like KEULE, SEC6 plays a physiological role in cytokinesis, and the SEC6-KEULE interaction may serve as a novel molecular linkage between arriving vesicles and membrane fusion machinery or directly regulate membrane fusion during cell plate formation in plants.