MicA, a novel protease adaptor in metabolic shutdown.

我们打算研究细胞如何通过激活“基因表达开关”来彻底改变自己的身份。这样的转变对于自然保持健康很重要，例如在胚胎发育中，胚胎发育始于相同的细胞，然后至关重要地转变为组成发育的人类的不同类型的细胞。相反，当细胞癌变或病原体入侵宿主时，这些转化会造成伤害。基因表达开关涉及一种不同的遗传指令程序被停用，并被一种导致细胞性质根本性转变的替代蛋白所取代。在这项研究中，我的团队将研究一种新发现的蛋白质--云母，它在细菌孢子形成过程中充当蛋白酶ClpC的适配器。我们有证据表明，随着孢子休眠，云母参与了新陈代谢的关闭。孢子形成是“医院超级细菌”持续存在的部分原因，因为孢子是一种长寿的细菌形式，对清洁剂具有抵抗力，并且在缺乏天然肠道微生物的患者中茁壮成长。我们打算在云母免费并与ClpC结合时，使用间接技术揭示云母的详细分子形状，因为即使使用强大的显微镜，它们也太小而看不见。我们专门测量蛋白质的形状和它们结合的方式，通过人工大量生产它们，并在细菌的帮助下作为我们的“蛋白质工厂”。然后，我们通过处理它们的行为来推断蛋白质的分子结构，当我们从它们身上反射X射线或将它们置于强磁场中时。每种技术都有其优缺点，但我们的组合方法可以产生补充信息，填补仅使用其中一种方法留下的空白。与微生物学家合作，我们将向彼此的实验提供信息，以建立细菌孢子形成中这种基因表达开关的机制图。例如，如果我们在我们的一种蛋白质中发现了一种突变，使其与其伴侣更紧密地结合在一起，我们的合作者可以在细菌内进行同样的突变，以测试它在生命系统中是否具有预期的效果。通过解决这个拼图，我们希望能够更好地设计新的抗生素，以应对日益严重的细菌耐药性问题，该项目还对理解新陈代谢和基因表达开关在健康和疾病的许多方面具有更长期的意义。

We propose to study the way cells can completely transform their identity by activating a 'gene expression switch'. Such transformations are important to naturally maintain health e.g. in embryo development which begins with identical cells which then crucially change into the different types of cells that make up a developed human. Conversely, these transformations can cause harm e.g. when cells become cancerous or pathogens invade hosts. A gene expression switch involves a distinct programme of genetic instruction being deactivated and replaced with an alternative that leads to radical transformation of the cell's nature.In this study my group will examine a newly discovered protein, MicA, which acts an adaptor to the protease ClpC during bacterial spore formation. We have evidence that MicA is involved in metabolic shut-down as the spore becomes dormant. Sporulation is partially responsible for the persistence of 'hospital superbugs' as spores are a long-lived bacterial form, resistant to cleaning agents and thriving in patients depleted of natural gut microflora.We intend to uncover the detailed molecular shapes of MicA when it is free and bound to ClpC using indirect techniques as they are too small to see even using powerful microscopes. We specialise in measuring protein shapes and the way they fit together by producing them artificially in large quantities, with the help of bacteria which act as our 'protein factories'. We then deduce the proteins' molecular structures by processing their behaviour when we bounce X-rays off them or put them in strong magnetic fields. Each of these techniques has its strengths and weaknesses but our combined approach can yield complementary information filling in the gaps left by using just one of the methods. Collaborating with a microbiologist we will feed information into each others' experiments to build up a mechanistic picture of this gene expression switch in bacterial spore formation. For example, if we identify a mutation in one of our proteins that makes it bind more tightly to its partner our collaborator can make the same mutation within bacteria to test whether it has the predicted effect in living systems.By solving this jigsaw puzzle we hope to be in a stronger position to design novel antibiotics to attack the increasing problem of bacterial drug resistance and the project also has longer term implications for understanding metabolism and gene expression switches in many aspects of health and disease.