RUI:The Paradox of Cellular Calcium Homeostasis During Vectorial Transfer: Spatial and Temporal Regulation of Ca Import/Export Proteins Using the Freshwater Crayfish Molting Model.

钙（Ca）对生物体的许多过程至关重要。钙通过专门的细胞（上皮细胞，如肠或鳃）进入人体；从那时起，必须根据需要将其从低浓度区域（细胞质或细胞内部）重新定向到高使用区域（例如细胞外或细胞外的生物矿化区）。钙通过一系列钙转运蛋白（钙通道、钙泵和钙交换器）的活动在细胞内外膜内移动。钙转运上皮提出了一个终极悖论，即，当细胞质水平保持在较低水平时，大量的钙是如何通过细胞的？利用细胞和分子方法，淡水小龙虾蜕皮模型将用于研究这些钙转运蛋白是如何随着时间的推移而调节的（比较蜕皮前后的高钙通量时期，以及蜕皮期间的钙平衡时期）。空间调节也将通过比较内膜和外膜上蛋白质的活性来研究。这项工作的目的是更好地了解不同钙转运蛋白阵列如何被调节以实现细胞钙稳态。这项研究将促进对膜钙转运的基本认识，并有可能影响生物医学的许多分支。它还将在两个主要的本科院校进行研究生和本科水平的学生培训，并将转化为符合国家科学教育标准的K-12课程。

Calcium (Ca) is critical to many processes in living organisms. Calcium enters the body through specialized cells (epithelia, like the gut or gills); from that point it must be redirected as needs dictate away from regions of low concentration (cytosol or cell interior) towards regions of high use (for example biomineralization zones that are extracellular or outside of cells). Calcium is moved within and between cells across internal and external membranes through the activity of an array of Ca transporting proteins (Ca channels, pumps and exchangers). Calcium transporting epithelia present the ultimate paradox, namely, how can vast amounts of Ca move through the cell while cytosolic levels are kept low? Using cellular and molecular approaches, the freshwater crayfish molting model will be used to study how these Ca transporting proteins are regulated over time (comparing periods of high Ca flux that occur just before and after molting, with periods of Ca balance during intermolt periods). Spatial regulation will also be studied by comparing activity of proteins on internal vs. external membranes. The goal of this work is to better understand how arrays of different Ca transporting proteins are regulated to achieve cellular Ca homeostasis. This research will advance the basic understanding of membrane Ca transport which has the potential to impact many branches of biomedicine. It will also result in student training at both graduate and undergraduate levels at two primarily undergraduate institutions and will be translated into the K-12 curriculum that is consistent with National Science Education Standards.