Regulatory mechanisms controlling type II phosphatidylinositol 4-kinase activity and its associated effector systems

生物分子进出细胞和在细胞内的运动代表了正常健康细胞功能几乎每个方面的关键过程。由于这些过程通常涉及通过载体将货物从细胞中的一个地方运送到另一个地方，因此它们被称为贩运途径。贩运途径往往很复杂，并受到严格的监管控制，以确保正确的货物以正确的数量到达正确的地点。毫不奇怪，运输途径中的缺陷可能导致人类和动物的严重疾病，这是由于货物错误递送或由于途径中的阻断而导致货物在细胞中积累的结果。我们也知道，由运输途径缺陷引起的疾病可能需要很长时间才能表现为临床症状，届时可能难以治疗。因此，如果我们要了解这些途径如何导致这些疾病的原因和进展，那么尽可能多地了解这些途径及其调节是很重要的。我们在这里建议，我们感兴趣的蛋白质分子，这是众所周知的PI 4KII α，我们已经工作了10多年，参与了重要的运输过程，包括一个称为内吞作用，用于将货物带入细胞。内吞作用也被用来发送不需要的分子进行破坏，甚至回收它们。这种途径甚至被病毒和细菌利用，进入细胞以建立感染。PI 4KII alpha是一种修饰脂肪样脂质分子PI的酶。PI存在于货物的膜载体中，并且已知PI 4KII α参与许多运输途径。然而，PI 4KII α在胞吞作用中的确切作用尚不清楚。我们以前已经表明，细胞失去功能的PI 4 KII α开始异常交通和积累一些货物。我们现在需要了解PI 4KII alpha在胞吞作用中是如何控制运输的。这一点的关键是进行实验，以找出是什么控制PI 4KII α及其脂质产物如何在膜上发挥作用。我们知道，并不是所有的细胞中的PI 4KII α是完全活跃在任何一个时间，我们相信，PI 4KII α只激活时，在需要的地方-如在运输过程中的载体。为了研究这一点，我们需要使用先进的显微镜技术，并使新的细胞探针，专门检测膜载体上的脂质，以显示这些水平的变化，在胞吞作用。膜的环境在控制PI 4KII α活性方面也起着重要作用，我们将研究其他脂质水平如何控制PI 4KII α。我们还将使用生物化学技术来发现可以打开和关闭PI 4KII α活性的因素。PI 4KII alpha是细胞运输机制中非常重要的一部分。在这笔赠款的帮助下，我们希望能为PI 4KII alpha和一般贩运途径的基础知识做出重大贡献。这项工作所产生的信息不仅对那些研究贩运途径的人有用，而且对那些对因有缺陷的贩运而发生的许多人类疾病感兴趣的人也有用。

The movement of biological molecules in to, out of, and within cells represent key processes underlying almost every aspect of normal, healthy cell function. Because these processes often involve the delivery of a cargo from one place in a cell to another via a carrier, they are known as trafficking pathways. Trafficking pathways are often complex and subject to tight regulatory control ensuring that the right cargo reaches the correct place in the right amount. Not surprisingly, defects in trafficking pathways can lead to serious disease in humans and animals as the result of cargo misdelivery or from cargo accumulating in cells because of a block in a pathway. It is also known that diseases caused by defects in trafficking pathways can take a long time to manifest as clinical symptoms by which time they may be difficult to treat. It is therefore important for us to learn as much as possible about these pathways and their regulation if we are to understand how they can contribute to the causes and progression of these diseases. We suggest here that our protein molecule of interest, which is known as PI4KIIalpha and upon which we have worked for more than 10 years, is involved in important trafficking processes including one called endocytosis that is used to bring cargo into cells. Endocytosis is also used to send unwanted molecules for destruction or even recycle them. This pathway is even exploited by viruses and bacteria gain entry to cells in order to establish infections. PI4KIIalpha is an enzyme that modifies a fat-like lipid molecule called PI. PI is found in membrane carriers of cargo and PI4KIIalpha is known to be involved in a number of trafficking pathways. However, exactly what PI4KIIalpha does in endocytosis is not known. We have previously shown that cells which lose functional PI4KIIalpha begin to abnormally traffic and accumulate some cargoes. We now need to understand how PI4KIIalpha controls trafficking during endocytosis. The key to this involves conducting experiments to find out what controls PI4KIIalpha and how its lipid products exert their actions on membranes. We know that not all of the PI4KIIalpha in cells is fully active at any one time and we believe that PI4KIIalpha is only activated when and where it is needed - such as on carriers during trafficking. To investigate this we need to use advanced microscopy techniques and make new cellular probes which specifically detect lipids on membrane carriers to show changes in levels of these during endocytosis. The environment of the membrane also plays an important role in controlling PI4KIIalpha activity and we will investigate how the levels of other lipids control PI4KIIa. We will also use biochemistry techniques to discover factors that can switch the activity of PI4KIIalpha on and off. PI4KIIalpha is an extremely important part of the cells trafficking machinery. With the aid of this grant we hope to contribute significantly to the body of basic knowledge of PI4KIIalpha and trafficking pathways in general. The information generated by this work will be useful for those working not only on trafficking pathways, but also those interested in the many human diseases which occur as the result of defective trafficking.