Endosomal traffic in the plant endomembrane system is a fundamental and complex process that controls many essential cellular, developmental, and physiological functions in plants, including cellular polarization, cytokinesis, metal ion homeostasis, pathogen defense, and hormone transport (1). The secretory and endocytic pathways represent two major anterograde protein transport routes for protein delivery into the vacuole in plant cells (Fig. 1A). In the secretory pathway, transportation of newly synthesized soluble vacuolar cargo proteins is mediated by the vacuolar sorting receptors (VSRs) (2). After delivery of the soluble cargos into an intermediate compartment, receptors are recycled by the attachment of conserved sorting nexins (SNXs) and the core subunits of retromer complex (VPS26, VPS29, and VPS35) to the membrane. Nevertheless, the precise localization of the SNXs and the retromer subunits, as well as the identity of the organelles from which VSRs are recycled, remains in debate (3, 4). During endocytosis, plasma membrane (PM) proteins are internalized and delivered into the trans-Golgi network (TGN)/early endosomes in plants (5). Ubiquitinated PM proteins are further sorted into the intralumenal vesicles of multivesicular bodies, previously identified as a prevacuolar compartment (6), by the endosomal sorting complex required for transport machinery for vacuolar degradation (7). Alternatively, PM proteins without a ubiquitin tag (or after removal of ubiquitin by a deubiquitinating enzyme) are recycled back to the PM from the TGN or recycling endosome (RE) (1, 8). In plants, numerous PM proteins undergo endocytosis and endosomal recycling, with the PIN-FORMED (PINs) transporters for the plant hormone auxin being the most studied (9). Polarized PM localization of PINs has a profound developmental importance and is tightly regulated by multiple endosomal trafficking routes, including endocytosis, endosomal recycling, and vacuolar degradation. PINs are internalized via clathrin-mediated endocytosis and then recycled back to the PM via the GNOM-positive putative RE …

中文翻译：

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激素调节蛋白质动力学以调节植物的生长[植物生物学]

植物膜系统中的内体运输是一个基本而复杂的过程，它控制着植物中许多重要的细胞，发育和生理功能，包括细胞极化，胞质分裂，金属离子稳态，病原体防御和激素转运（1）。分泌途径和内吞途径代表了两种主要的顺行蛋白质转运途径，用于将蛋白质递送到植物细胞的液泡中（图1A）。在分泌途径中，新合成的可溶性液泡货物蛋白的运输由液泡分选受体（VSR）介导（2）。将可溶性货物输送到中间室后，通过将保守的分选神经毒素（SNX）和逆转录复合物的核心亚基（VPS26，VPS29和VPS35）附着到膜上，回收受体。尽管如此，SNXs的精确定位和retromer亚基，以及从该视觉敏感受体被再循环的细胞器，遗体在辩论的身份（3，4）。在胞吞过程中，质膜（PM）蛋白被内化并传递到植物中的反式高尔基网络（TGN）/早期内体中（5）。泛素化的PM蛋白被进一步分选到多囊体的腔内囊泡中，该囊泡先前已被鉴定为疏液前区隔（6），通过运输机械进行液泡降解所需的内体分选复合物（7）。可替代地，PM蛋白质，而不泛素标记（或通过去泛素化酶除去泛素之后）被再循环从TGN回PM或回收核内体（RE）（1，8）。在植物中，许多PM蛋白经历了内吞作用和内体再循环，其中对植物激素生长素的PIN形成（PIN）转运蛋白研究最多（9）。PINs的极化PM定位具有重要的发展意义，并受到多种内体运输途径（包括内吞，内体再循环和液泡降解）的严格调控。PIN通过网格蛋白介导的内吞作用而被内在化，然后通过GNOM阳性推定的RE再循环回到PM中。