K. A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Botanicheskaya Str. 35, 127276 Moscow, Russia.
Int J Mol Sci. 2023 Jan 8;24(2):1251. doi: 10.3390/ijms24021251.
The aim of this study was to elucidate whether the membrane nanodomain protein Flot1 is involved in vesicular transport pathways and regulation of the P-type H-ATPase content in plasma membrane of under salt stress. Transmission electron microscopy revealed changes in the endosomal system of root cells due to knockout mutation SALK_205125C (). Immunoblotting of the plasma membrane-enriched fractions isolated from plant organs with an antibody to the H-ATPase demonstrated changes in the H-ATPase content in plasma membrane in response to the mutation and salt shock. Expression levels of the main H-ATPase isoforms, and , as well as endocytosis activity of root cells determined by endocytic probe FM4-64 uptake assay, were unchanged in the mutant. We have shown that Flot1 participates in regulation of the H-ATPase content in the plasma membrane. We hypothesized that Flot1 is involved in both exocytosis and endocytosis, and, thus, contributes to the maintenance of cell ion homeostasis under salt stress. The lack of a pronounced phenotype under salt stress conditions may be due to the assumed ability of to switch vesicular transport to alternative pathways. Functional redundancy of Flot proteins may play a role in the functioning of these alternative pathways.
本研究旨在阐明膜纳米域蛋白 Flot1 是否参与了盐胁迫下液泡运输途径和质膜 P 型 H+-ATPase 含量的调节。透射电子显微镜显示，由于 SALK_205125C（）突变，根细胞的内体系统发生了变化。用针对 H+-ATPase 的抗体对植物器官中分离的富含质膜的级分进行免疫印迹分析表明，H+-ATPase 的含量在质膜中对突变和盐休克有反应。在 突变体中，主要 H+-ATPase 同工型、和的表达水平以及通过 FM4-64 摄取测定法测定的根细胞的内吞活性均未改变。我们已经表明 Flot1 参与了质膜中 H+-ATPase 含量的调节。我们假设 Flot1 参与胞吐作用和胞吞作用，从而有助于在盐胁迫下维持细胞离子稳态。在盐胁迫条件下缺乏明显的表型可能是由于假定的 Flot1 能够将囊泡运输切换到替代途径。Flot 蛋白的功能冗余可能在这些替代途径的功能中发挥作用。
