MRC Program grant

有丝分裂，即复制的染色体在子细胞之间分裂的过程，需要细胞发生重大变化。年代的架构。因此，一组有序结构暂时被另一组取代，即染色体分离机制。这主要是由细胞内磷酸化特定蛋白质的酶引起的，这样磷酸的负电荷就会改变蛋白质的结构和功能。这些酶被称为蛋白激酶，其中大约有十种不同的酶在有丝分裂中起作用。蛋白质磷酸化受到另一组酶的反对，蛋白质磷酸酶在适当的时间和地点去除磷酸基团。在过去的20年里，我们对有丝分裂蛋白激酶的细胞功能有了大量的了解，但对磷酸酶的了解却很落后。本研究旨在促进我们对蛋白磷酸酶参与与蛋白激酶功能相关的有丝分裂调节网络的理解。然而，这并不是简单的激酶使细胞进入有丝分裂而磷酸酶将其取出。这是因为不同的有丝分裂激酶促进亚细胞结构的拆卸和组装，因为激酶和磷酸酶在不同的有丝分裂阶段具有正调控和负调控功能。细胞分裂的调控回路在进化上是古老的，在所有动物细胞中都是保守的，所以我们可以用果蝇作为一个模型遗传系统来研究这些回路。我们已经确定了这样一个有丝分裂调控回路，包括一个主要的有丝分裂蛋白磷酸酶和两个蛋白激酶，并开发了一个有效的遗传筛选来识别这个网络的组成部分。在这里，我们建议进一步确定该网络的组成部分，并研究它们的功能相互关系。我们还使用了另一种系统，从培养的细胞中一个接一个地去除果蝇的100个左右的蛋白磷酸酶，看看这是如何影响有丝分裂过程的。我们已经知道，这种鉴定出的蛋白磷酸酶与一些新的参与者一起具有有丝分裂作用。我们将专注于确定这些蛋白磷酸酶如何调节有丝分裂装置的主要成分，从而使子细胞之间的两组染色体能够准确分离。这些过程的高度保守性导致我们之前在果蝇中发现的主要有丝分裂蛋白激酶被识别为治疗人类癌症的潜在药物靶点。对蛋白磷酸酶的研究也具有类似的重要性。

Mitosis, the process whereby replicated chromosomes are partitioned between daughter cells, requires major changes to the cell?s architecture. Thus one set of ordered structures is temporarily replaced by another, the machinery for chromosome segregation. This is largely brought about by enzymes that phosphorylate specific proteins within the cell such that the negative charge of the phosphate changes the structure and function of the protein. These enzymes are known as protein-kinases, of which about ten different ones act in mitosis. Protein phosphorylation is opposed by another group of enzymes, the protein-phosphatases that remove phosphate groups at appropriate times and places. Whereas we have learned a great deal about the cellular functions of the mitotic protein-kinases over the last 20 years, our understanding of the phosphatases lags behind. This research aims to advance our understanding of the involvement of protein-phosphatases in the mitotic regulatory networks in relation to protein-kinase function. However, it is not simply the case that kinases get a cell into mitosis and phosphatases get it out again. This is because different mitotic kinases promote both the disassembly and assembly of sub-cellular structures and because both kinases and phosphatases can have positive and negative regulatory functions at different mitotic stages. The regulatory circuits for cell division are evolutionarily ancient and are conserved in all animal cells and so we can use the fruit fly as a model genetic system to study these circuits. We have identified such a mitotic regulatory circuit that involves a major mitotic protein-phosphatase and two protein-kinases and have developed an effective genetic screen to identify components of this network. Here we propose to identify further components of this network and study their functional inter-relationships. We have also used another system for removing each of the 100 or so protein phosphatases of the fruit fly one by one from cultured cells to see how this affects the mitotic process. This identified protein-phosphatases we already knew had mitotic roles together with a number of new players. We will focus on determining how these protein-phosphatases regulate principal components of the mitotic apparatus to enable accurate segregation of the two sets of chromosomes between daughter cells. The high conservation of these processes led to the recognition of major mitotic protein kinases, that we had previous identified in the fruit-fly, as potential drug targets for treating human cancer. The proposed work on protein phosphatases can have similar importance.