Malpighian Tubule Transport Physiology: Mechanisms and Regulation

马氏小管运输生理学：机制和调节

• 批准号: 0078058
• 负责人: Klaus Beyenbach
• 金额: --
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-08-01 至 2006-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0078058&HistoricalAwards=false
• 关键词: Malpighian; Tubule; Transport; Physiology; Mechanisms

The overall goal of this project is to identify and characterize current-generating and current-dissipating transport systems in the natural environment of an intact principal cell in the Malpighian tubule of the yellow fever mosquito (Aedes aegypti). In the basolateral cell membrane, the aim is to characterize K channels, and putative Na and Ca channels. In the apical membrane, the focus is on current generation by the V-type H+-ATPase, testing the effects of voltage and the two substrates of the pump, H and ATP. Investigating how current is dissipated across this membrane may lead to the discovery of a new family of antiporters.Outside principal cells, the grant proposes to characterize the nature of the shunt taken by Cl during transepithelial secretion. One hypothesis to be tested is that the stellate cell serves as the shunt pathway. The alternate hypothesis considers insect septate junctions to offer a paracellular pathway for Cl. They hypothetical model proposes that septate junctions house a Cl channel-like structure that is regulated by the diuretic peptide leucokinin.Experiments described in this proposal will demonstrate how proton pump, channels, symporters and antiporters are organized in principal cells in insect Malpighian tubules to secrete Na and K into the tubule lumen via a transcellular path. Studies of the shunt pathway will show how Cl is secreted, presumably via a paracellular path. Together, these studies will reveal the combinatorial arrangement of the molecular building blocks of epithelial transport: pumps, channels, carriers, and junctions and how they interact to secrete NaCl, KCl, and water into the tubule lumen. Results from the proposed studies of an ATP-driven pump in an intact cell will be of wide interest to biologists.

该项目的总体目标是确定和表征黄热病蚊子（埃及伊蚊）马尔比氏管中完整主细胞的自然环境中产生电流和耗散电流的运输系统。在基底外侧细胞膜中，目的是表征K通道，以及假定的Na和Ca通道。在顶膜中，重点研究v型H+-ATP酶产生电流，测试电压和泵的两种底物H和ATP的影响。研究电流如何在这层膜上耗散可能会导致发现一个新的反转运蛋白家族。在主细胞外，该基金提出表征Cl在经上皮分泌过程中分流的性质。一个有待验证的假设是，星状细胞充当了分流通路。另一种假设认为昆虫的分离连接为Cl提供了细胞外通路。他们的假设模型提出，分离的连接处有一个Cl通道样结构，由利尿肽白蛋白调节。本提案中描述的实验将展示质子泵、通道、正转运体和反转运体如何在昆虫马尔比氏小管的主细胞中组织起来，通过跨细胞途径将Na和K分泌到小管腔中。分流通路的研究将显示Cl是如何分泌的，可能是通过细胞旁通路。总之，这些研究将揭示上皮运输的分子组成部分的组合排列：泵、通道、载体和连接，以及它们如何相互作用以分泌NaCl、KCl和水进入小管腔。对完整细胞中atp驱动泵的研究结果将引起生物学家的广泛兴趣。