The CLIC-1 Chloride Channel: Structure and Function

CLIC-1 氯离子通道：结构和功能

• 批准号: 7169345
• 负责人: JOHN C EDWARDS
• 金额: $ 4.42万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7169345
• 关键词: beta adrenergic receptor; chloride channels; conformation; gel filtration chromatography; high performance liquid chromatography; hydropathy; lipid bilayer membrane; mass spectrometry; membrane activity; membrane lipids; membrane permeability; membrane proteins; membrane structure; phospholipids; protein isoforms; protein localization; protein structure function; solubility; vesicle /vacuole

DESCRIPTION (provided by applicant): Chloride channel proteins are essential to a host of cellular functions and chloride channel dysfunction is known to be involved in the pathogenesis of a number of human disease states. We have identified and begun to characterize a family of chloride channel proteins which are structurally unrelated to other known chloride channels. One member of this family, CLIC-1, is expressed in many cell types and is very highly expressed in the apical domain of renal proximal tubule cells. Subcellular localization studies indicate that it is present in membrane compartments along the endosomal pathway. We have recently demonstrated that recombinant CLIC-1 functions as a chloride selective channel when purified from bacteria and reconstituted in phospholipid membranes. Unlike typical ion channel proteins, CLIC proteins are present in cells both in a membrane inserted form and in a soluble form in the cytoplasm. Over the past several years, a number of membrane proteins have been reported to be able to assume conformations which are soluble in aqueous solution. In some instances, it is clear that these proteins can partition between membrane-inserted and soluble states and that this partitioning is important in regulation of the activity of these proteins. We have now found that CLIC-1 is capable of inserting into phospholipid membranes from the aqueous phase and this inserted CLIC-1 can function as a chloride channel. In this grant application, we propose to study the biochemical basis and biological relevance of functional membrane insertion of this important protein.

描述（由申请人提供）：氯离子通道蛋白对于许多细胞功能至关重要，并且已知氯离子通道功能障碍与许多人类疾病状态的发病机制有关。我们已经鉴定并开始表征氯离子通道蛋白家族，它们在结构上与其他已知的氯离子通道无关。 CLIC-1 是该家族的一个成员，在许多细胞类型中表达，并且在肾近曲小管细胞的顶端区域表达非常高。亚细胞定位研究表明它存在于沿着内体途径的膜区室中。我们最近证明，当从细菌中纯化并在磷脂膜中重建时，重组 CLIC-1 可充当氯离子选择性通道。 与典型的离子通道蛋白不同，CLIC 蛋白以膜插入形式和细胞质中可溶形式存在于细胞中。在过去的几年中，据报道许多膜蛋白能够呈现可溶于水溶液的构象。在某些情况下，很明显这些蛋白质可以在膜插入状态和可溶状态之间分配，并且这种分配对于调节这些蛋白质的活性很重要。我们现在发现CLIC-1能够从水相插入磷脂膜，并且插入的CLIC-1可以起到氯离子通道的作用。在这项拨款申请中，我们建议研究这种重要蛋白质的功能性膜插入的生化基础和生物学相关性。