Class III phosphoinositide 3-kinase Vps34 in autophagy and endocytosis

描述(申请人提供)：Vps34是一种脂蛋白激酶，通过产生脂质信号分子3-磷酸肌醇来调节膜转运途径，如内吞作用和自噬。内吞作用是细胞摄取细胞外物质和跨膜蛋白，并将它们分类到适当的目的地的过程。内吞作用对于细胞获得营养和适当的生长控制是必要的。自噬是一个进化上保守的过程，它通过起到管家的作用，并在细胞处于压力下时提供额外的营养来促进细胞存活。由于内吞和自噬都是癌症发生和抵抗治疗的重要细胞事件，它们已成为设计新的癌症治疗方法的靶点。因此，重要的是要了解这些细胞事件是如何调节的。虽然Vps34与细胞吞噬和自噬有关，但由于缺乏特定的抑制物，其确切作用的确定一直受到阻碍。利用基因敲除策略，我们最近报道了Vps34在自噬小体的形成和内吞作用的晚期发挥着重要作用，但在内吞的早期可能是必不可少的。本研究旨在通过研究Vps34缺失细胞中早期内吞小体的功能、内小体成熟的过程和晚期内吞小体的功能来确定Vps34在内吞作用中的确切作用，以及2)自噬是如何通过Vps34依赖或独立的机制来调节的。这些研究将有助于更清楚地了解Vps34在细胞吞噬和自噬中的确切作用。这些信息对于理解Vps 34的多方面功能以及 针对细胞吞噬或自噬的抗癌治疗药物的设计。

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.