Osmolyte Channels in Fish Erthrocytes:Functional and Molecular Properties

鱼类红细胞渗透压通道的功能和分子特性调节细胞体积是一种重要的生理机制。 细胞经历细胞外液的生理稀释和细胞分裂，最初膨胀，然后在几分钟内恢复正常的细胞体积。 这是通过调节它们的细胞内溶质浓度来实现的，以通过转运包括离子和有机成分在内的药理活性细胞成分（渗透剂）来匹配细胞外环境。在细胞肿胀期间，细胞膜中的特定蛋白质通道被激活，这导致从肿胀细胞释放的渗透调节剂增加。 一旦细胞体积恢复，通道失活，导致从先前溶胀的细胞释放渗透调节剂的停止。 虽然渗透压通道的功能特性已经详细说明，但它们的分子身份仍然不清楚。 有证据表明，细胞膜蛋白，AE，参与激活渗透剂运输过程中的细胞肿胀在鱼红细胞。 最近发现，有三个基因表达的AE蛋白在滑冰（Raja erinacea）红细胞。 这项研究解决了以下问题：哪些基因参与了红细胞膜中AE蛋白的表达？ 在细胞膜上表达的三种蛋白质中，哪一种起着渗透压转运蛋白的作用？ 在细胞膨胀过程中激活转运蛋白的调节因素是什么？ 完整的滑冰红细胞，分离的红细胞膜，和AE蛋白表达系统在青蛙卵将被用来确定：1。三种AE蛋白中的哪一种在青蛙细胞中表达。 2.表达于蛙卵细胞膜的三种AE蛋白中哪一种形成渗透调节剂转运通道。3.红细胞膜中的哪些AE蛋白定位于细胞膜表面的脂质结构域（“筏”）。 4.在红细胞膜中发现的与AE蛋白相连的几种外周蛋白中，哪一种参与细胞膜转运蛋白的调节。 这些研究将为细胞体积控制中涉及的分子和调控机制提供见解。本科生和研究生将从布朗大学，山沙漠岛生物研究实验室和参与现有的REU计划的项目招募。 此外，研究经验将赞助从普罗维登斯和农村缅因州招募的高中生。

Osmolyte Channels in Fish Erythrocytes: Functional and Molecular PropertiesLeon Goldstein Regulation of cell volume is an important physiological mechanism. Cells undergoing physiological dilution of the extracellular fluid and cell division, initially swell, and then, within minutes, restore their normal cell volume. This is accomplished by adjusting their intracellular solute concentrations to match that of the extracellular environment via the transport of osmotically active cell constituents (osmolytes) including ions and organic constituents. During cell swelling, specific protein channels are activated in the cell membrane, which lead to increased release of osmolytes from the swollen cells. Once cell volume is restored the channels are deactivated resulting in cessation of release of osmolytes from the previously swollen cells. Although the functional characteristics of the osmolyte channels have been detailed, their molecular identity is still not clear. Evidence suggests that the cell membrane protein, AE, is involved in the activation of osmolyte transport during cell swelling in fish red blood cells. Recently it has been discovered that there are three genes for the expression of AE proteins in skate (Raja erinacea) red blood cells. This research addresses the questions: Which genes are involved in expression of AE proteins in the red blood cell membranes? Which of the three proteins expressed in the cell membranes function as osmolyte transporters? What are the regulatory factors that activate the transporters during cell swelling? Intact skate red blood cells, isolated red blood cell membranes, and AE protein expression systems in frog eggs will be used to determine: 1. Which of the three AE proteins are expressed in the frog cell. 2. Which of the three AE proteins expressed in the frog egg cell membranes form osmolyte transport channels. 3.Which of the AE proteins in red blood cell membranes localize to lipid domains ('rafts') found on the surface of the cell membranes. 4. Which of several peripheral proteins found in the red blood cell membranes and attached to the AE protein are involved in the regulation of the cell membrane transporters. These studies will provide insights into the molecular and regulatory mechanisms involved in the control of cell volume. Undergraduate and graduate students will be recruited for the project from Brown University , the Mount Desert Island Biological Research Lab and from participation in an existing REU program. In addition, research experiences will be sponsored for high school students recruited from Providence and rural Maine.