溶酶体/液泡是内吞、自噬等多条运输途径的汇聚点。相关囊泡与溶酶体/液泡的融合造成其膜组分增加。关于细胞如何减少溶酶体/液泡的膜组分以维持稳态，目前尚缺充分探索。..我们前期工作发现“早平台期液泡降解现象(EVT)”：在随营养消耗而进入生长平台期的酵母细胞中，液泡上多种膜蛋白进入液泡内腔被降解。EVT需要利用ESCRT复合体、Rab控制的囊泡融合因子、Atg8三组蛋白。..参照近年相关研究，我们提出假说从内体-液泡互作角度阐释EVT的机制： ESCRT通过调控内体的Rab级联转化促进Ypt7的激活；Ypt7进而调控液泡膜的动态变化、实现EVT底物降解；Atg8通过与相关蛋白的互作参与EVT调控。本项目旨在对这一假说及其替代假说进行充分检验，辨析EVT底物降解的实现方式，并确定Atg8的调控靶点。..我们的工作有望促进对环境改变引起的液泡动态变化之机制和其中涉及的内体-液泡互作模式的认知。

The lysosome/vacuole sits at the crossroad of multiple intracellular trafficking routes including endocytosis and autophagy. Fusion with incoming vesicles results in increases of lysosomal/vacuolar membrane biomass. At present, little is known regarding how cells reduce the membrane constituents of this organelle to counterbalance material influx. ..In our preliminary study, we identified the “early-stationary phase vacuole turnover/EVT” phenomenon: as yeast cells enter stationary phase upon gradual nutrient depletion, integral membrane proteins with diverse functions are translocated from the surface of vacuoles into the lumen of this organelle and degraded. This process relies on at least three groups of proteins: the ESCRT complexes, vesicle fusion factors under the control of Rab proteins, and Atg8. ..Taking recent publications in related areas into consideration, we advocate an interpretation of EVT mechanism based on endosome-vacuole interactions: The ESCRT machinery participates in the Rab conversion process on endosomes to promote the activation of Ypt7 (Rab7 homologue); Ypt7 in turn regulates the dynamic behavior of vacuoles, leading to the turnover of EVT substrate; during this process, Atg8 engages in the regulation of EVT by protein-protein interaction(s). The aims of this project are to perform extensive tests on this and other potential hypotheses to clarify the mechanism underlying EVT substrate turnover, and to identify the target of Atg8 regulation. ..Our study will provide a distinctive perspective on how environmental changes regulate dynamics of vacuoles and the integral contribution of endosome-vacuole interactions therein.