ROP GTPases Act with the Receptor-Like Protein PAN1 to Polarize Asymmetric Cell Division in Maize
ROP GTPases Act with the Receptor-Like Protein PAN1 to Polarize Asymmetric Cell Division in Maize
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DOI：
10.1105/tpc.111.085597
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发表时间：
2011-06-01
期刊：
影响因子：
11.6
通讯作者：
Smith, Laurie G.
中科院分区：
文献类型：
--
作者：
Humphries, John A.;Vejlupkova, Zuzana;Smith, Laurie G.
植物Rho家族GTP酶(Rop)主要是因为它们在细胞极化生长中的功能而被研究。我们先前的研究表明，玉米(Zea Mays)富含Leu重复的受体样蛋白PANGLOSS1(PAN1)在气孔发育过程中促进不对称辅助母细胞(SMC)分裂的极化。在这里，我们证明了玉米I型ROPS 2和9与PAN1一起在这一过程中发挥作用。ROP2/9功能的部分丧失导致PAN1突变体的SMC分裂极性表型较弱，并强烈增强这一表型。与PAN1一样，ROP在SMC中以不对称的方式积累。黄色荧光蛋白-ROP2的过度表达与其在SMC中的非定位化和SMC分裂的异常定向有关。ROP的极化定位依赖于PAN1，而PAN1的定位对ROP的耗竭和去极化不敏感。膜相关的I型ROPS显示非离子洗涤剂在PAN1突变体中的溶解度增加，这表明PAN1在ROPS的膜分配中发挥作用。最后，通过相互免疫共沉淀实验证明，玉米组织提取液中的内源PAN1和ROP蛋白在物理上相互关联。这项研究证明了ROPs在植物细胞分裂和细胞生长的极化过程中起着关键作用，并揭示了受体样蛋白在ROPs空间定位中的作用。
Plant Rho family GTPases (ROPs) have been investigated primarily for their functions in polarized cell growth. We previously showed that the maize (Zea mays) Leu-rich repeat receptor-like protein PANGLOSS1 (PAN1) promotes the polarization of asymmetric subsidiary mother cell (SMC) divisions during stomatal development. Here, we show that maize Type I ROPs 2 and 9 function together with PAN1 in this process. Partial loss of ROP2/9 function causes a weak SMC division polarity phenotype and strongly enhances this phenotype in pan1 mutants. Like PAN1, ROPs accumulate in an asymmetric manner in SMCs. Overexpression of yellow fluorescent protein-ROP2 is associated with its delocalization in SMCs and with aberrantly oriented SMC divisions. Polarized localization of ROPs depends on PAN1, but PAN1 localization is insensitive to depletion and depolarization of ROP. Membrane-associated Type I ROPs display increased nonionic detergent solubility in pan1 mutants, suggesting a role for PAN1 in membrane partitioning of ROPs. Finally, endogenous PAN1 and ROP proteins are physically associated with each other in maize tissue extracts, as demonstrated by reciprocal coimmunoprecipitation experiments. This study demonstrates that ROPs play a key role in polarization of plant cell division and cell growth and reveals a role for a receptor-like protein in spatial localization of ROPs.