Centre for Plant Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.
Plant Cell. 2010 Dec;22(12):3992-4008. doi: 10.1105/tpc.110.078436. Epub 2010 Dec 21.
Plant vacuolar sorting receptors (VSRs) display cytosolic Tyr motifs (YMPL) for clathrin-mediated anterograde transport to the prevacuolar compartment. Here, we show that the same motif is also required for VSR recycling. A Y612A point mutation in Arabidopsis thaliana VSR2 leads to a quantitative shift in VSR2 steady state levels from the prevacuolar compartment to the trans-Golgi network when expressed in Nicotiana tabacum. By contrast, the L615A mutant VSR2 leaks strongly to vacuoles and accumulates in a previously undiscovered compartment. The latter is shown to be distinct from the Golgi stacks, the trans-Golgi network, and the prevacuolar compartment but is characterized by high concentrations of soluble vacuolar cargo and the rab5 GTPase Rha1(RabF2a). The results suggest that the prevacuolar compartment matures by gradual receptor depletion, leading to the formation of a late prevacuolar compartment situated between the prevacuolar compartment and the vacuole.
植物液泡分选受体（VSRs）展示细胞质 Tyr 基序（YMPL），用于网格蛋白介导的正向运输到前液泡区室。在这里，我们表明，相同的基序对于 VSR 回收也是必需的。在拟南芥 VSR2 中的 Y612A 点突变导致 VSR2 在稳定状态水平上从前液泡区室到高尔基网络的定量转移，当在烟草中表达时。相比之下，L615A 突变体 VSR2 强烈渗漏到液泡中，并积累在一个以前未发现的隔室中。后者被证明与高尔基堆栈、高尔基网络和前液泡区室不同，但以高浓度的可溶性液泡货物和 rab5 GTPase Rha1（RabF2a）为特征。结果表明，前液泡区室通过受体逐渐耗竭而成熟，导致形成位于前液泡区室和液泡之间的晚期前液泡区室。
