Structural analysis of the bestrophin anion channel Best2

黄斑黄蛋白阴离子通道 Best2 的结构分析

• 批准号: 10020765
• 负责人: Aaron Paul Owji
• 金额: $ 4.55万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-01 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10020765
• 关键词: Affect; Anions; Aqueous Humor; Calcium; Calcium Binding; Chloride Channels; Ciliary epithelium; Dependence; Drug Design; Electron Microscopy; Electrophysiology (science); Epithelial Cells; Eukaryota; Exhibits; Eye; Eye diseases; Family; Generations; Genes; Glaucoma; Glutamic Acid; Glycine; Goals; Homologous Gene; Human Genome; Hydrophobicity; Ion Channel; Ions; Klebsiella pneumoniae; Lead; Link; Lysine; Membrane; Modeling; Molecular; Molecular Conformation; Mus; Mutation; Pathway interactions; Pharmacology; Physiologic Intraocular Pressure; Play; Positioning Attribute; Proteins; Protomer; Research; Retina; Retinal Degeneration; Role; Sequence Analysis; Serine; Sodium Chloride; Structural Models; Structure; Structure of retinal pigment epithelium; Testing; Therapeutic; Time; Tissues; Translating; Transmembrane Domain; Work; base; basolateral membrane; cell type; constriction; cryogenics; design; experimental study; high intraocular pressure; mutant; nanomolar; paralogous gene; particle; response; seal; side effect; structured data; therapeutic target; therapy development

Bestrophins are a family of pentameric calcium-activated chloride channels that respond to intracellular calcium (Ca2+) by allowing the flow of monovalent anions across the membrane. Bestrophins are activated in the presence of nanomolar to micromolar concentrations of Ca2+ and exhibit a time- and concentration -dependent inactivation of current. The structural basis behind activation and subsequent inactivation in response to increasing Ca2+concentrations has not been fully elucidated at the molecular level. Bestrophins are expressed in a wide variety of tissues, and often within specialized cell types. Best1 is expressed in the retinal pigmented epithelial (RPE) cells of the eye and mutations in the BEST1 gene lead to a class of retinal degenerative diseases called bestrophinopathies. BEST2, on the other hand, is expressed in the basolateral membrane of the nonpigmented ciliary epithelial (NPE) cells of the eye, where it has been linked to generation of intraocular pressure, suggesting it may represent a pharmacological target to treat glaucoma. Sequence analysis of Best1-4 reveals Best2 has a difference in the cytosolic pore constriction, a region previously implicated in channel gating. The goal of this project is to 1) generate a structural model to explain Ca2-dependent activation and inactivation in a mammalian Best2 channel, including electrophysiological analysis and structural analysis of rationionally designed mutants to test the model, and 2) investigate the structural differences within the cytosolic constriction of Best2 that distinguish it from other bestrophins. Completion of these aims will inform on the function of bestrophins throughout the body, and will guide structure-based drug design to specifically target Best2 and not other bestrophins, which may have potential to treat glaucoma.

BestRophins是一个对五钙激活的氯化物通道的家族 细胞内钙（Ca2+）通过允许单价阴离子在整个膜上的流动。 在存在纳摩尔至微摩尔浓度的Ca2+和 表现出时间和浓度依赖性的电流失活。背后的结构基础 响应于Ca2+浓度升高的激活和随后的失活尚未 在分子水平上完全阐明。 Bestrophins在多种组织中表达，并且 通常在专业的细胞类型中。 Best1在视网膜色素上皮（RPE）中表达 眼睛的细胞和最佳1基因突变导致一类视网膜退行性疾病 称为Bestrophinopathies。另一方面，最好的2在基底外侧膜中表示 眼睛的非纤维纤维上皮（NPE）细胞的含量 眼内压，表明它可能代表治疗青光眼的药理靶标。 Best1-4的序列分析表明，BEST2在胞质孔隙收缩中有差异，A 以前与通道门控有关的区域。该项目的目标是1）产生结构 解释Ca2依赖性激活和失活的模型 包括生理生理分析和生产设计突变体的结构分析 测试模型，以及2）研究胞质收缩内的结构差异 最好的2将其与其他Bestrophins区分开。这些目标的完成将告知 BestRophins在整个身体中的功能，并将指导基于结构的药物设计 特别是针对Best2，而不是其他BestRophins，可能具有治疗青光眼的潜力。