Regulation of autophagy induction by the Vps34 complex: structural and functional studies.

这项工作将确定脂蛋白激酶Vps34及其脂类产物PI3P调节自噬的机制。自噬(源于希腊的自食)是细胞在饥饿期间从自身物质中产生营养物质的一种方式。由于几个原因，自噬的途径对生物体的健康非常重要。自噬是所有类型细胞的正常生理基础，也是延长寿命的关键因素。受损的细胞成分会成为自噬的底物，并被有效地清除。这会导致细胞内部的周期性清理，并允许重要蛋白质和细胞器的再生。值得注意的是，当自噬被抑制时，细胞显示出氧化损伤的迹象，因为它们功能失调的线粒体无法被移除，并继续产生活性氧物种。同样，抑制自噬在很大程度上促进了突变的聚集性蛋白(通常是自噬降解的底物)的积累，从而导致神经退行性疾病。自噬对于新生时期也是至关重要的：不能进行自噬的动物在出生后不久就会死亡，因为它们在无法从外部获得营养的过程中无法从自己的资源中产生营养。自噬的途径始于细胞内部形成一种名为自噬小体的新型双膜囊泡。这些自噬小体(任何时候都可能有数百个)包裹着细胞物质，并将其运送到一个被称为溶酶体的可降解细胞器进行消化。由于各种与健康相关的原因，目前人们对寻找增强或抑制自噬的方法非常感兴趣，最好的起点是了解自噬是如何形成的。我们以前的工作表明，自噬形成的信号之一是通过Vps34酶的活性合成一种名为PI3P的脂类。这导致一系列中间结构的形成，最终形成自噬小体。然而，这种情况是如何发生的，以及中间结构最终如何导致自噬是一个谜，我们将结合细胞生物学和结构生物学的专业知识，以找到调节自噬开始的Vps34复合体的结构，我们将使用生化和显微镜详细描述从PI3P到自噬形成的途径。

This work will determine the mechanism by which the lipid kinase Vps34 and its lipid product PI3P regulate autophagy. Autophagy (from the Greek self-eating) is a way for cells to generate nutrients from their own material during times of starvation. The pathway of autophagy is very important for the health of an organism for several reasons. Autophagy underpins the normal physiology of all cell types, and is a critical contributor to life-span extension. Cellular components that are damaged become substrates for autophagy and are efficiently eliminated. This leads to a periodic clean-up of the cell interior and allows for regeneration of important proteins and organelles. Of note, when autophagy is suppressed cells exhibit signs of oxidative damage because their dysfunctional mitochondria cannot be removed and continue to produce reactive oxygen species. Similarly, suppression of autophagy contributes in a significant way to the build-up of mutant aggregate-prone proteins (which are normally substrates of autophagic degradation) that cause neuro-degenerative disorders. Autophagy is also critical for the neo natal period: animals that cannot mount autophagy die soon after birth because they cannot generate nutrients from their own resources during a period where they do not obtain nutrients from the outside.The pathway of autophagy starts when a novel double membrane vesicle called autophagosome is formed in the cell interior. These autophagosomes (which can be hundreds in number at any one time) enclose cellular material and deliver it to a degradative organelle called lysosome for digestion. There is currently high interest in finding ways to enhance or suppress autophagy for various health-related reasons and the best place to start is to undesratnd how autophagosomes are formed.Our previous work has shown that one of the signals for formation of autophagosomes is the synthesis of a lipid called PI3P by the activity of the Vps34 enzyme. This results in the formation of a series of intermediate structures that eventually give rise to an autophagosome. However exactly how this happens and how the intermediate structures eventually lead to an autophagosome is a mystery and will be tackled by our proposed work.We will combine expertise in cell biology and structural biology in order to find the structure of the Vps34 comlex that regulates the start of autophagy, and we will use biochemistry and microscopy to describe in detail the pathway that leads from PI3P to autophagosome formation.