Functional Studies of Calmyrin

描述（由申请人提供）：本研究的目的是了解钙蛋白的功能，钙蛋白是一种与阿尔茨海默病相关蛋白早老素-2（PS2）相互作用的肉豆蔻酰化钙结合蛋白。我们的初步数据表明钙蛋白是一种钙传感器：钙结合引发蛋白质的大的构象变化。我们认为钙诱导的钙蛋白构象变化对于促进其动态细胞内靶向和与蛋白质如PS2结合是重要的。 我们发现钙蛋白的过度表达诱导钙调节异常和细胞凋亡。然而，钙蛋白诱导钙调节异常和细胞凋亡的机制尚不清楚。钙蛋白与蛋白磷酸酶2 B（钙调神经磷酸酶）的调节亚基钙调神经磷酸酶B具有最高的同源性。在酵母双杂交筛选中，我们分离出钙蛋白酶，一种假定的丝氨酸磷酸酶。我们的初步结果表明，钙蛋白酶可能类似于钙调神经磷酸酶，因为它可能是由钙蛋白调节的催化磷酸酶组分。与该假设雅阁，我们发现钙蛋白以钙依赖性方式结合钙蛋白酶，并且钙蛋白和钙蛋白酶的共表达导致钙蛋白酶在细胞核中的定位的显著改变，并刺激NFATc-GFP报告基因的细胞核输入。我们还发现MSV驱动的钙蛋白构建体的转基因表达导致小鼠脱发和过早死亡。我们认为，钙蛋白是一种重要的蛋白质，并建议使用多管齐下的方法来表征钙蛋白和钙蛋白酶的功能。我们提出了四个具体目标：目标1，确定钙蛋白在细胞功能中的作用。目的2、对钙蛋白酶进行表征和功能测定。目的3、鉴定MSV-钙蛋白转基因小鼠。目的4，构建特异性组织器官钙蛋白基因缺失小鼠。从拟议的研究中获得的结果将导致更好地了解细胞和生物体中的钙蛋白，并最终了解其在健康和疾病中的作用

DESCRIPTION (provided by applicant): The goal of this research is to understand the function of calmyrin, a myristoylated calcium-binding protein that interacts with the Alzheimer's disease related protein, presenilin-2 (PS2). Our preliminary data suggest calmyrin is a calcium sensor: calcium binding triggers a large conformational change in the protein. We believe that the calcium-induced change in calmyrin conformation is important for facilitating its dynamic intracellular targeting and binding to proteins, such as PS2. We found overexpression of calmyrin induces calcium dysregulation and apoptosis. However, the mechanism(s) by which calmyrin induces calcium dysregulation and apoptosis is not known. Calmyrin shares highest homology with calcineurin B, the regulatory subunit of protein phosphatase 2B (calcineurin). In a yeast two-hybrid screen, we isolated calmitase, a putative serine phosphatase. Our preliminary results suggest that calmitase might be analogous to calcineurin, in that it could be the catalytic phosphatase component that is regulated by calmyrin. In accord with this hypothesis, we found calmyrin binds calmitase in a calcium-dependent manner and that co-expression of calmyrin and calmitase results in a dramatic alteration in calmitase localization in the nucleus and stimulates nuclear import of an NFATc-GFP reporter. We also found that transgenic expression of an MSV-driven calmyrin construct causes alopecia and premature death in mice. We believe that calmyrin is an important protein and propose to use a multi-pronged approach to characterize calmyrin and calmitase functions. We propose four specific aims: Aim 1, to determine the role of calmyrin in cell function. Aim 2, to characterize and determine the function of calmitase. Aim 3, to characterize MSV-calmyrin transgenic mice. Aim 4, to generate mice that are disrupted of the calmyrin gene in specific organs and tissues. The results obtained from the proposed research will lead to a better understanding of calmyrin in cells and organisms, and ultimately, its role in health and disease