US-Poland Research on Hormonal Control of Calcium Transport Across the Plasma Membrane in Hepatocytes

这个美国-波兰的研究项目之间的博士凯瑟琳F。拉努埃 宾夕法尼亚州立大学好时医疗中心和杰西 波兰华沙Nencki研究所的Duszinski将确定 并表征催化激素依赖性 细胞外钙离子流入肝细胞。 研究人员 将在原代培养中研究fura-2负载的肝细胞，使用 全细胞荧光数字成像系统 膜片钳显微注射技术，以确定电流 假定的钙通道的电压关系，以及 钙内流的焓及其pH依赖性。 初步 实验表明，进入细胞的钙转运不是 依赖于钙动员受体的激素占用， 细胞膜或细胞中的IP 3水平， 取决于细胞内激素的消耗程度 可释放的钙储存。 这些储存的钙消耗 刺激钙以分级的方式进入细胞。 的 研究人员将测试一个假设， 内质网中的酶加工并释放到 胞质溶胶调节质膜钙的代谢物 磁导率 他们将设计实验来证明 这种可扩散代谢物的存在并表征它。 研究人员计划使用一种血浆钙抑制剂 膜转运蛋白作为监测钙转运蛋白的手段 活性的肝细胞质膜囊泡负载Fura-2。 他们将使用囊泡分析系统来筛选 推定的调节剂并作为以后溶解的基础， 重构和纯化。 %%% 生物学的这个项目实现了推进 科学知识，使领先的专家在联合国 国家和东欧联合收割机互补人才和汇集 在共同感兴趣和有能力的领域提供资源。

This U.S.-Poland research project between Dr. Kathryn F. Lanoue of Pennsylvania State University Hershey Medical Center and Jerzy Duszinski of the Nencki Institute of Warsaw, Poland, is to identify and characterize the transporter which catalyzes hormone dependent influx of extracellular calcium into liver cells. The researchers will study fura-2 loaded hepatocytes in primary culture, using a fluorescence digital imaging system in conjunction with whole cell patch clamp microinjection techniques, to determine the current voltage relationships of the putative calcium channel, as well as the enthalpy of calcium influx and its Ph dependence. Preliminary experiments indicate the calcium transport into the cell is not dependent on hormone occupancy of calcium mobilizing receptors in the plasma membrane, or on IP3 levels in the cell but it is dependent on the extent of depletion of intracellular hormone releasable calcium stores. Calcium depletion of these stores stimulates calcium entry into the cell, in a graded manner. The researchers will test the hypothesis that a calcium sensitive enzyme in the endoplasmic reticulum elaborates and releases to the cytosol a metabolite which regulates plasma membrane calcium permeability. They will design experiments to demonstrate the existence of such a diffusible metabolite and to characterize it. The researchers plan to use an inhibitor of the calcium plasma membrane transporter as a means to monitor calcium transporter activity in hepatocyte plasma membrane vesicles loaded with fura-2. They will use the vesicular assay system to screen the influence of putative regulators and as a basis for later solubilization, reconstitution, and purification. %%% This project in biology fulfills the program objective of advancing scientific knowledge by enabling leading experts in the United States and Eastern Europe to combine complementary talents and pool resources in areas of strong mutual interest and competence.