Department of Food Science, University of Tennessee, Food Safety and Processing Building, 2600 River Dr., Knoxville, TN 37996, USA; Institute of Biology, Laboratory of Cell and Molecular Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland.
Institute of Biology, Laboratory of Cell and Molecular Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland.
Plant Sci. 2018 Jan;266:9-18. doi: 10.1016/j.plantsci.2017.10.007. Epub 2017 Oct 20.
Soluble vacuolar proteins reach their compartments of final accumulation through the binding with specific transmembrane cargo receptors. In Arabidopsis thaliana two different families of receptors have been characterized. The AtVSRs (Vacuolar Sorting Receptor), which are known to be involved in the protein sorting to lytic vacuoles (LV), and the AtRMRs (Receptor Membrane RING-H2), for which there is less evidence for a role in the traffic to the protein storage vacuole (PSV). In this study we investigated the localization and tissue expression of two RMRs (AtRMR1 and 2) in their species of origin, A. thaliana. Our experiments using leaf protoplasts and transgenic plants supported previous results of subcellular localization in Nicotiana benthamiana that visualized AtRMR1 and 2 in the cisternae of endoplasmic reticulum (ER) and in the trans-Golgi network (TGN), respectively. The promoter activities of AtRMR1 and AtRMR2 detected in transgenic A. thaliana lines suggest that the expression of these two receptors only partially overlap in some organs and tissues. These results suggest that AtRMR1 and 2 are not functionally redundant, but could also interact and participate in the same cellular process in tissues with an overlapping expression.
可溶性液泡蛋白通过与特定的跨膜货物受体结合，到达其最终积累的隔室。在拟南芥中，已经鉴定出两种不同的受体家族。AtVSRs（液泡分拣受体），已知其参与到溶酶体（LV）的蛋白质分拣中，而 AtRMRs（受体膜环指蛋白-H2）在蛋白质储存液泡（PSV）的运输中作用的证据较少。在这项研究中，我们研究了两种 RMRs（AtRMR1 和 2）在其原始物种拟南芥中的定位和组织表达。我们使用叶原生质体和转基因植物进行的实验支持了之前在烟草原生质体中进行的亚细胞定位的结果，即可视化 AtRMR1 和 2 分别位于内质网（ER）的小泡和高尔基体的 cisterna 中。在转基因拟南芥系中检测到的 AtRMR1 和 AtRMR2 的启动子活性表明，这两个受体在某些器官和组织中的表达仅部分重叠。这些结果表明，AtRMR1 和 2 不是功能冗余的，但也可以在表达重叠的组织中相互作用并参与相同的细胞过程。
