Differential degradation of PIN2 auxin efflux carrier by retromer-dependent vacuolar targeting
Differential degradation of PIN2 auxin efflux carrier by retromer-dependent vacuolar targeting
复制标题
DOI：
10.1073/pnas.0808073105
复制
发表时间：
2008-11-18
影响因子：
11.1
通讯作者：
Friml, Jiri
中科院分区：
文献类型：
--
作者：
Kleine-Vehn, Juergen;Leitner, Johannes;Friml, Jiri
所有真核细胞在细胞表面存在一组特定的质膜蛋白，其调节对内部和外部线索的反应，并且其活性也受蛋白质降解的调节。我们的特点是溶解液泡依赖的降解膜蛋白在拟南芥液泡靶向结合定量蛋白质分析的体内可视化的手段。我们表明，液泡靶向途径是由多种货物，包括PIN形成（PIN）外排载体植物激素生长素。PIN 2空泡靶向的体内可视化揭示了其响应于环境信号（例如重力）的差异降解。相反，极性PIN传递到基底质膜，这取决于囊泡运输调节剂ARF-GEF GNOME，PIN分选到裂解液泡途径需要额外的布雷菲德菌素A敏感的ARF-GEF活性。此外，我们确定了推定的retromer组件分选NEXIN 1（SNX 1）和VACUOLAR PROTEIN SORTING 29（VPS 29）作为该途径中的重要因素，并提出了retromer复合物的作用，以检索PIN蛋白从后期/前液泡室回到回收途径。我们的数据表明，ARF GEF和retromer依赖的过程中调节PIN排序的液泡中的拮抗方式，并说明仪器化的微调生长素通量在向重力反应的机制。
All eukaryotic cells present at the cell surface a specific set of plasma membrane proteins that modulate responses to internal and external cues and whose activity is also regulated by protein degradation. We characterized the lytic vacuole-dependent degradation of membrane proteins in Arabidopsis thaliana by means of in vivo visualization of vacuolar targeting combined with quantitative protein analysis. We show that the vacuolar targeting pathway is used by multiple cargos including PIN-FORMED (PIN) efflux carriers for the phytohormone auxin. In vivo visualization of PIN2 vacuolar targeting revealed its differential degradation in response to environmental signals, such as gravity. In contrast to polar PIN delivery to the basal plasma membrane, which depends on the vesicle trafficking regulator ARF-GEF GNOM, PIN sorting to the lytic vacuolar pathway requires additional brefeldin A-sensitive ARF-GEF activity. Furthermore, we identified putative retromer components SORTING NEXIN1 (SNX1) and VACUOLAR PROTEIN SORTING29 (VPS29) as important factors in this pathway and propose that the retromer complex acts to retrieve PIN proteins from a late/pre-vacuolar compartment back to the recycling pathways. Our data suggest that ARF GEF- and retromer-dependent processes regulate PIN sorting to the vacuole in an antagonistic manner and illustrate instrumentalization of this mechanism for fine-tuning the auxin fluxes during gravitropic response.