Class III phosphoinositide 3-kinase Vps34 in autophagy and endocytosis

描述（由申请人提供）：Vps34是一种脂质激酶，通过产生磷酸肌醇3-磷酸（一种脂质信号分子）来调节膜运输途径，如内吞和自噬。内吞作用是细胞吸收细胞外物质和跨膜蛋白质，并将它们分类到适当的目的地的过程。胞吞作用是细胞获取营养和适当的生长控制所必需的。自噬是一种进化上保守的过程，它通过充当管家的角色来促进细胞存活，并在细胞处于压力下提供额外的营养。由于内吞和自噬都是癌症发展和治疗抵抗的重要细胞事件，它们已成为设计新型癌症治疗药物的靶点。因此，了解这些细胞事件是如何被调控的是很重要的。尽管Vps34与内吞作用和自噬都有关系，但由于缺乏特异性抑制剂，确定其确切作用一直受到阻碍。利用基因敲除策略，我们最近报道了Vps34在自噬体的形成和内吞作用的后期阶段起主要作用，但在内吞体的早期可能是不需要的。本研究旨在通过检测Vps34缺陷细胞中早期核内体的功能、核内体成熟过程和晚期核内体的功能来确定1)Vps34在胞吞作用中的确切作用，以及2)自噬是如何通过Vps34依赖或独立机制调节的。这些研究将有助于更清楚地了解Vps34在内吞作用和自噬中的确切作用。这一信息对于了解Vps34的多方面功能至关重要

DESCRIPTION (provided by applicant): Vps34 is a lipid kinase that regulates membrane trafficking pathways like endocytosis and autophagy by generating phosphoinositol 3-phosphate, a lipid signaling molecule. Endocytosis is the process by which cells take up extracellular materials and transmembrane proteins, and sort them to their proper destinations. Endocytosis is necessary for cells to acquire nutrients and for appropriate growth control. Autophagy is an evolutionarily conserved process that promotes cell survival by serving a housekeeping role, and by providing extra nutrients when the cell is under stress. As both endocytosis and autophagy are important cellular events in cancer development and resistance to therapy, they have become targets for designing novel cancer therapeutics. Therefore, it is important to understand how these cellular events are regulated. Although Vps34 is implicated in both endocytosis and autophagy, determining its precise role has been hampered by the lack of specific inhibitors. Using a genetic knockout strategy we recently reported that Vps34 has a major role in autophagosome formation and the late stages of endocytosis, but may be dispensable at the early endosome. This proposal is designed to determine 1) the precise role of Vps34 during endocytosis by examining the functions of the early endosome, the process of endosome maturation and the functions of the late endosome in Vps34-deficient cells, and 2) how autophagy is regulated via Vps34 dependent or independent mechanisms. These studies will help provide a clearer picture of the exact roles of Vps34 in endocytosis and autophagy. This information will be critical for understanding the multifaceted functions of Vps34 and for the design of anti-cancer therapeutics targeting endocytosis or autophagy.