The molecular roles of polycystin in cytokinesis

总结 常染色体显性遗传性多囊肾病（ADPKD）是人类最常见的遗传性疾病之一， 影响了超过60万美国人其特征是充满液体的囊肿逐渐发展， 肾脏中细胞增殖增加，通常导致终末期肾衰竭。尽管发现 两个多囊蛋白基因PKD1和PKD2的突变解释了所有ADPKD病例，原因尚不清楚。我们 已经发现了多囊蛋白在分裂酵母细胞分裂中的一种新功能，这将为改变 在ADPKD中观察到细胞增殖。我们发现裂殖酵母多囊蛋白Pkd2p定位于细胞分裂 调节细胞分裂最后阶段胞质分裂的位点。在这里，我们建议使用这种模式生物， 确定多囊蛋白在胞质分裂中的分子作用。我们的中心假设是Pkd2p调节这两种蛋白， 收缩环和胞质分裂期间通过其作为离子通道的活性的钙信号。 目的1研究Pkd2p对胞质分裂收缩环的调节作用。我们发现PKD2突变 令人惊讶地导致环的异常收缩，并且大量的突变细胞处于渗透压下， 应力我们将首先确定Pkd2p是否调节膨压。然后我们将确定Pkd2p如何 调节可收缩环的组装和收缩。我们希望证实Pkd2调节 通过调节细胞渗透压来组装收缩环。 目的2研究Pkd2p对胞质分裂过程中子细胞分离的调控作用。我们的初步数据 表明Pkd2p在子细胞的分离中起重要作用。我们建议确定如何 Pkd2p调节分裂细胞中的钙浓度。我们还将研究Pkd2p如何衰减 调节细胞分离的重要信号通路。我们希望证实Pkd2p调节了 分裂细胞中的钙浓度并拮抗基本信号传导途径。 目的3研究Pkd2p蛋白不同结构域在胞质分裂中的作用。PKD2P具有三种不同的 具有未知功能的域。我们建议确定Pkd2p的定位和功能，当这些 域被单独移除。我们希望证实，只有两个结构域的Pkd2p是必不可少的每一个 在胞质分裂中起着独立的作用。 尽管多年来对多囊蛋白的研究，但对其在细胞分裂中的功能知之甚少。我们的惊喜 这一观察将为多囊蛋白在发病机制中对细胞增殖的调节提供新的见解 的ADPKD。我们将在我们的研究中使用创新的显微镜方法。我们建议大力促进 本科生研究，以造福大量的第一代大学生在大学 托莱多和训练他们成为沉浸在定量细胞生物学研究。

SUMMARY Autosomal dominant polycystic kidney disease (ADPKD) is one of the most common human genetic disorders, affecting more than 600,00 Americans. It is characterized by progressive development of liquid-filled cysts and increased cell proliferation in the kidney, often resulting in terminal renal failure. Despite of the discovery that mutations of two polycystin genes PKD1 and PKD2 account for all cases of ADPKD, it remains unclear why. We have uncovered a novel function of polycystin in cell division in fission yeast, that will shed new light on altered cell proliferation observed in ADPKD. We found that fission yeast polycystin Pkd2p localizes to the cell division site to regulate cytokinesis, the last stage of cell division. Here we propose to use this model organism to determine the molecular roles of polycystin in cytokinesis. Our central hypothesis is that Pkd2p regulates both the contractile ring and the calcium signaling during cytokinesis through its activity as an ion channel. Aim 1 To determine how Pkd2p regulates the contractile ring in cytokinesis. We found that the pkd2 mutation surprisingly leads to abnormal constriction of the ring and a large number of the mutant cells are under osmotic stress. We will first determine whether Pkd2p regulates the turgor pressure. We will then determine how Pkd2p regulates the assembly and the constriction of the contractile ring. We expect to confirm that Pkd2 modulates the assembly of the contractile ring by regulating the cellular osmolality. Aim 2 To determine how Pkd2p regulates the daughter cell separation in cytokinesis. Our preliminary data showed that Pkd2p plays an essential role in the separation of daughter cells. We propose to determine how Pkd2p regulates the calcium concentration in dividing cells. We will also examine how Pkd2p attenuates an essential signaling pathway that regulates the cell separation. We expect to confirm that Pkd2p regulates the calcium concentration in dividing cells and antagonizes the essential signaling pathway. Aim 3 To determine how different domains of Pkd2p protein work in cytokinesis. Pkd2p possesses three distinct domains with unknown functions. We propose to determine both localization and function of Pkd2p when these domains are removed individually. We expect to confirm that only two domains of Pkd2p are essential with each playing a separate role in cytokinesis. Despite years of research on polycystins, little is known about its function in cell division. Our surprising observation would provide novel insight into the regulation of cell proliferation by polycystins in the pathogenesis of ADPKD. We will use innovative microscopy method in our study. We propose to strongly promote undergraduate research to benefit the large number of first-generation college students at the University of Toledo and to train them to become immersed in quantitative cell biology research.