Dynamic phosphorylation in the post-transcriptional regulation of the Trypanosoma brucei cell cycle

细胞如何确保它们正确地复制自己？当细胞生长和分裂时，它们必须在称为细胞周期的有序过程中协调两个子细胞之间的内容物的复制和分裂。了解调节细胞周期的许多过程很重要，因为许多疾病，如癌症和糖尿病，都涉及这种调节的破坏。本项目将使用一种称为布氏锥虫的生物体作为简化系统来研究细胞周期控制机制的重要部分。 蛋白质是通过将DNA转录成信使RNA，然后将信使RNA翻译成蛋白质而产生的。在这个过程中，调控可以发生在许多不同的点，以控制细胞周期中何时产生蛋白质以及产生多少蛋白质。通过添加或去除磷酸基团修饰蛋白质，这一过程称为动态磷酸化，是细胞周期调控中的重要控制机制。我们正在研究布氏锥虫，因为它不调节DNA的转录。相反，所有的调节都发生在转录之后，这使我们能够专注于这些事件。T.布氏杆菌利用动态磷酸化来调节细胞周期尚不清楚，但可能是新颖的。为了了解布氏锥虫是如何调节其细胞周期的，我们将首先测量在细胞周期的不同时间点产生多少每种蛋白质，以及它们是否被磷酸化。通过将蛋白质分解成更小的称为肽的链，我们可以使用称为质谱仪的复杂机器来测量成千上万的肽和磷酸化位点。这些测量可用于确定在每个时间点存在多少每种蛋白质和磷酸化位点。这将产生对细胞周期的描述，可以解释为解释它是如何调节的模型。然后，我们将进行实验，看看模型预测是否正确。如果我们的实验表明模型不正确，我们可以使用这些新信息来改进模型，直到预测与我们的实验一致。由于布氏锥虫是牛的寄生虫和人类的病原体，我们在这项研究中所了解的将有助于开发新的药物对抗寄生虫。更好地了解调节细胞周期的基本过程也将对其他重要疾病如癌症和糖尿病产生影响。

How do cells make sure that they duplicate themselves correctly? When cells grow and divide, they must coordinate the duplication and division of their content between the two daughter cells in an ordered process known as the cell cycle. Understanding the many processes that regulate the cell cycle is important as many diseases such as cancer and diabetes involve a breakdown in this regulation. This project will study an important part of the cell cycle control mechanism using an organism called Trypanosoma brucei as a simplified system. Proteins are produced by transcribing DNA into messenger RNA, and then translating the messenger RNA into proteins. Regulation can occur at many different points during this process to control when and how much protein is produced within the cell cycle. Modification of proteins by adding or removing a phosphate group, a process called dynamic phosphorylation, is an important contol mechanism in cell cycle regulation. We are studying Trypanosoma brucei as unusually it does not regulate the transcription of DNA. Instead, all the regulation occurs after transcription, allowing us to focus on these events. The way that T. brucei uses dynamic phosphorylation to regulate the cell cycle is not understood, but is likely to be novel. To understand how Trypanosoma brucei is able to regulate its cell cycle, we will first measure how much of each protein is produced at different time points in the cell cycle, and whether they are phosphorylated. By breaking proteins down into smaller chains called peptides, we can measure many thousands of peptides and phosphorylation sites using sophisticated machine called mass spectrometers. These measurements can be used to determine how much of each protein and phosphorylation site is present at each time point. This will produce a description of the cell cycle that can be interpreted to make a model explaining how it is regulated. We will then conduct experiments to see if what the model predicts is correct. If our experiments show the model is not right, we can use this new information to improve the model until the predictions agree with our experiments. As Trypanosoma brucei is a parasite of cattle and a pathogen of humans, what we learn in this study will contribute to the development of new drugs against the parasite. Better understanding of the fundamental processes regulating the cell cycle will also have an impact on other important diseases such as cancer and diabetes.