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

这项工作将确定脂质激酶Vps34及其脂质产物PI3P调节自噬的机制。自噬（来源于希腊语自食）是细胞在饥饿时从自身物质中产生营养物质的一种方式。自噬途径对生物体的健康非常重要，原因如下。自噬支撑着所有细胞类型的正常生理，是延长寿命的关键因素。受损的细胞成分成为自噬的底物，并被有效地消除。这导致了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，细胞表现出氧化损伤的迹象，因为它们的功能失调的线粒体不能被移除并继续产生活性氧。同样，自噬的抑制在很大程度上有助于突变的聚集易感性蛋白（通常是自噬降解的底物）的积累，从而导致神经退行性疾病。自噬对新生期也至关重要：不能进行自噬的动物在出生后不久就会死亡，因为它们不能从自己的资源中获得营养，因为它们不能从外界获得营养。当细胞内部形成一种叫做自噬体的新型双膜囊泡时，自噬途径就开始了。这些自噬体（在任何时候都有数百个）包裹细胞物质，并将其传递给一种称为溶酶体的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，而最好的起点是不了解自噬体是如何形成的。我们之前的工作表明，自噬体形成的信号之一是通过Vps34酶的活性合成一种称为PI3P的脂质。这导致一系列中间结构的形成，最终产生自噬体。然而，这究竟是如何发生的，以及中间结构最终如何导致自噬体是一个谜，将由我们提出的工作来解决。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，我们将使用生物化学和显微镜来详细描述从PI3P到自噬体形成的途径。

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.