A systems approach to elucidation of protein lipidation during virus infection

病毒是小的感染体，是专性寄生虫，因为它们只在宿主细胞内复制。要导致疾病，它们必须进入特定的靶细胞，克服感染障碍，并与适当的细胞机制接触，然后重新定向，以制造更多的自我复制。这项应用涉及人类主要病毒之一--疱疹病毒。这些病毒在人群中引起的疾病范围从中等但频率较高的疾病，如口疮、水痘或腺热，到虽然频率较低但可能极其严重和危及生命的疾病，包括眼部感染、新生儿疾病以及外周和中枢神经系统疾病。它们对免疫抑制的患者，如移植受者和艾滋病患者尤其危险。虽然我们有一些有效的药物，但它们的使用有很大的局限性，而且它们只对疱疹病毒的一部分有效。为了发现新的治疗机会，我们必须彻底了解复制的机制。这样的理解可能会导致设计可能更广泛有效的新型抗病毒药物的基本方法。宿主细胞蛋白和病毒蛋白在它们合成后(或在合成过程中)用一系列不同类型的分子进行修饰。这个过程通常被称为翻译后修饰，它在改变潜在靶蛋白的结构、定位、稳定性和功能方面发挥着基础性作用。因此，在病毒感染方面，蛋白质修饰可以作用于宿主细胞的蛋白质，影响它们支持病毒生长或应对感染和发动抗病毒攻击的能力。宿主蛋白修饰原则上可以保持不受影响，或者特定物种可以由宿主或病毒诱导，而其他物种可能下调。同样，病毒蛋白的修饰可以影响它们的功能，或重新聚集到组装颗粒中，影响它们在细胞内和细胞外的运输，或它们克服宿主反应的能力。这种修饰的一种常见类型被称为脂化，即蛋白质与一系列脂类(类脂肪分子)中的任何一种共价偶联。这代表了改变蛋白质的关键调节机制，从而调节包括膜靶向、细胞内蛋白质和细胞器运输、从细胞外到细胞内传递的信号网络、细胞结构、代谢途径、神经传递和免疫反应等过程。因此，蛋白质脂化在正常的生物功能和疾病进展中起着重要的作用。有四种主要类型的脂质修饰，它们可以以不同的组合发生在蛋白质上，改变蛋白质的位置和功能。然而，与其他类型的蛋白质修饰相比，人们对脂肪修饰的了解普遍较少，而且我们对被修饰的宿主和病毒蛋白质的范围的了解是不完整的。这是因为最常用的方法缺乏敏感性，产生结果的速度可能很慢，而且不容易接受利用遗传和蛋白质生物信息学进步的高通量分析。我们的目标是开发新的化学技术与高通量方法相结合，研究病毒和宿主蛋白的脂肪作用在疱疹病毒感染中的作用。这项工作不仅将对唇化在这一背景下的身份和作用产生新的见解，而且还将产生可用于其他系统的新的探测器和方法。它将极大地加速我们对感染的理解，以及我们在其他疾病系统中进行类似研究的能力，而不仅仅是传染病。它将能够高通量筛选潜在的新疗法类别，并将为多学科工作提供路线图，将化学和生物学结合在一起，以产生对疾病过程的新见解。

Viruses are small infectious agents and are obligate parasites in that they replicate only inside host cells. To cause disease, they must enter specific target cells, overcome barriers to infection and engage with the appropriate cellular machinery which they redirect to make more copies of themselves. This application concerns one of a major group of human viruses, the herpesviruses. These viruses cause diseases ranging from moderate but with high frequency in the population, such as cold sores, chicken pox or glandular fever, through to diseases that while less frequent, can be extremely severe and life threatening, including eye infections, diseases in newborn infants, as well as peripheral and central nervous system diseases. They are particularly dangerous in immunosuppressed patients such as transplant recipients and in AIDS patients. While we have some effective drugs, there are significant limitations with their use and they are effective only against a subset of the herpesviruses. To identify new therapeutic opportunities we must have a thorough understanding of the mechanisms of replication. Such understanding may lead to a rationale way to design novel antiviral agents which may be more broadly effective. Host cell proteins and viral proteins are modified after (or during) their synthesis with a series of different types of molecules. This process is generally termed post-translational modification and it plays a fundamental role in changing the structure, localisation, stability and function of the potential target proteins. Therefore in terms of virus infection, protein modification can be on host cell proteins and affect their ability to support virus growth or to respond to infection and mount an antiviral attack. Host protein modification can in principle remain unaffected, or specific species can be induced by the host, or by the virus, while other species may be down-regulated. Likewise modification of virus proteins can affect their function, or recruitment into assembly particles, their transport within and out of a cell or their ability to overcome host responses. One general type of such modification is called lipidation, wherein proteins are covalently coupled to any of a series of lipids (fat like molecules). This represents a key regulatory mechanism in altering proteins and thus regulating processes including membrane targeting, intracellular protein and organelle transport, signalling networks relaying communication from outside to inside the cell, cell structure, metabolic pathways, neurotransmission and immune responses. As such protein lipidation plays a profound role in normal biological functioning and disease progression. There are four broad types of lipid modification and they can take place on proteins in different combinations, altering the location and function of proteins. However lipidation is broadly less understood than other sorts of protein modification and our knowledge of the range of host and viral proteins which are modified is incomplete. This is because the most frequently utilised approaches lack sensitivity, can be slow to yield results and are not readily amenable to high-throughput analysis exploiting advances in genetic and protein bioinformatics. We aim to develop novel chemical technologies combined with high-throughput approaches on the role of lipidation of virus and host proteins in herpesvirus infection. Not only will this work yield novel insight into the identity and role of lipidation in this context, it will produce new probes and methodologies available for other systems. It will hugely accelerate our understanding of infection and our ability to perform similar studies in other disease systems not only in infectious diseases. It will enable high-throughput screening of potential new classes of therapeutics and it will provide a roadmap for multidisciplinary working bringing together chemistry and biology to yield novel insight into disease processes.