Trafficking of Vacuolar Proteins: The Crucial Role of Arabidopsis Vacuolar Protein Sorting 29 in Recycling Vacuolar Sorting Receptor
Trafficking of Vacuolar Proteins: The Crucial Role of Arabidopsis Vacuolar Protein Sorting 29 in Recycling Vacuolar Sorting Receptor
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DOI：
10.1105/tpc.112.103481
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发表时间：
2012-12-01
期刊：
影响因子：
11.6
通讯作者：
Hwang, Inhwan
中科院分区：
文献类型：
--
作者：
Kang, Hyangju;Kim, Soo Youn;Hwang, Inhwan
逆转录酶参与哺乳动物溶酶体分选受体的回收。拟南芥逆转录酶复合体的组成部分液泡蛋白分选 29 (VPS29) 在将储存蛋白运输到蛋白质储存液泡中发挥着至关重要的作用。然而，尚不清楚液泡分选受体（VSR）在运输到裂解液泡（LV）期间是否或如何从液泡前室（PVC）再循环到跨高尔基体网络（TGN）。在这里，我们报告 VPS29 在可溶性蛋白从 TGN 到 PVC 到 LV 的运输中发挥着重要作用。 maigo1-1 (mag1-1) 突变体在 VPS29 中存在敲低突变，在将两种可溶性蛋白（拟南芥 aleurain 样蛋白 (AALP)：绿色荧光蛋白 (GFP) 和 sporamin：GFP）运输到 LV 方面存在缺陷，但在将膜蛋白运输到 LV 或质膜或通过分泌途径运输到 LV 或质膜方面存在缺陷。 AALP：GFP 和 sporamin：mag1-1 原生质体中的 GFP 在 TGN 中积累，但也分泌到培养基中。在 mag1-1 突变体中，VSR1 无法从 PVC 循环到 TGN；相反，很大一部分被转移到了LV； VSR1 过度表达挽救了这一缺陷。此外，内源 VSR 在 mag1-1 植物中表达水平较高。基于这些结果，我们提出，在可溶性蛋白运输到 LV 的过程中，VPS29 在将 VSR 从 PVC 回收到 TGN 方面发挥着至关重要的作用。
The retromer is involved in recycling lysosomal sorting receptors in mammals. A component of the retromer complex in Arabidopsis thaliana, vacuolar protein sorting 29 (VPS29), plays a crucial role in trafficking storage proteins to protein storage vacuoles. However, it is not known whether or how vacuolar sorting receptors (VSRs) are recycled from the prevacuolar compartment (PVC) to the trans-Golgi network (TGN) during trafficking to the lytic vacuole (LV). Here, we report that VPS29 plays an essential role in the trafficking of soluble proteins to the LV from the TGN to the PVC. maigo1-1 (mag1-1) mutants, which harbor a knockdown mutation in VPS29, were defective in trafficking of two soluble proteins, Arabidopsis aleurain-like protein (AALP): green fluorescent protein (GFP) and sporamin: GFP, to the LV but not in trafficking membrane proteins to the LV or plasma membrane or via the secretory pathway. AALP: GFP and sporamin: GFP in mag1-1 protoplasts accumulated in the TGN but were also secreted into the medium. In mag1-1 mutants, VSR1 failed to recycle from the PVC to the TGN; rather, a significant proportion was transported to the LV; VSR1 overexpression rescued this defect. Moreover, endogenous VSRs were expressed at higher levels in mag1-1 plants. Based on these results, we propose that VPS29 plays a crucial role in recycling VSRs from the PVC to the TGN during the trafficking of soluble proteins to the LV.