A systems approach to elucidation of protein lipidation during virus infection

病毒是小型传染因子，是专性寄生虫，因为它们只在宿主细胞内复制。为了引起疾病，它们必须进入特定的目标细胞，克服感染障碍，并与适当的细胞机制接触，它们重新定向以制造更多的自身拷贝。这一应用涉及人类病毒的一个主要群体，疱疹病毒。这些病毒引起的疾病范围从人群中出现频率较高的中度疾病，如唇疱疹、水痘或腺热，到出现频率较低但可能极其严重并危及生命的疾病，包括眼睛感染、新生儿疾病以及周围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，而且它们只对一小部分疱疹病毒有效。为了确定新的治疗机会，我们必须彻底了解复制的机制。这样的理解可能导致一种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合成后（或合成过程中）被一系列不同类型的分子修饰。这一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、稳定性和功能方面起着重要作用。因此，在病毒感染方面，蛋白质修饰可以在宿主细胞蛋白上，影响它们支持病毒生长或对感染作出反应并发动抗病毒攻击的能力。宿主蛋白修饰原则上不受影响，或者宿主或病毒可以诱导特定物种，而其他物种可能被下调。同样，对病毒蛋白的修饰可以影响它们的功能、组装颗粒的募集、它们在细胞内外的运输或它们克服宿主反应的能力。这种修饰的一种一般类型被称为脂化，其中蛋白质与一系列脂质（脂肪样分子）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信息的信号网络、细胞结构、代谢途径、神经传递和免疫反应等过程。因此，蛋白质脂化在正常生物功能和疾病进展中起着深远的作用。脂质修饰有四种类型，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，与其他种类的蛋白质修饰相比，人们对脂化的了解较少，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，产生结果的速度很慢，并且不容易适用于利用遗传和蛋白质生物信息学进展的高通量分析。我们的目标是开发新的化学技术，结合高通量方法，研究病毒和宿主蛋白脂化在疱疹病毒感染中的作用。这项工作不仅会对这种情况下脂化的身份和作用产生新的见解，还会为其他系统提供新的探针和方法。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，而不仅仅是在传染病中。它将使潜在的新型治疗药物的高通量筛选成为可能，并将为将化学和生物学结合起来的多学科工作提供路线图，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.