Cellular regulation of Sodium-activated Ion Channels

钠激活离子通道的细胞调节

• 批准号: 8185062
• 负责人: LEONARD K KACZMAREK
• 金额: $ 35.17万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-26 至 2016-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8185062
• 关键词: Action Potentials; Adult; Affect; Amino Acid Sequence; Amino Acids; Animals; Antibodies; Architecture; Binding; Biochemical; Biological; Biological Assay; Brain; C-terminal; Cardiac Myocytes; Cell membrane; Cells; Chemosensitization; Development; Disease; Distal; Drug Delivery Systems; Epitopes; FMR1; Face; Fluorescence Resonance Energy Transfer; Fragile X Mental Retardation Protein; Fragile X Syndrome; Genes; Genetic; Human; Hypoxia; Immunoprecipitation; Impairment; In Vitro; Inherited; Injury; Intellectual functioning disability; Ion Channel; Knockout Mice; Lead; Mass Spectrum Analysis; Membrane Proteins; Messenger RNA; Molecular Conformation; Mus; Mutate; N-terminal; Neurodevelopmental Disorder; Neurons; Pattern; Peptides; Play; Potassium Channel; Property; Protein Binding; Protein Binding Domain; Protein Isoforms; Proteins; RNA Binding; RNA Splicing; RNA-Binding Proteins; Regulation; Role; Site-Directed Mutagenesis; Slice; Sodium; Structure; Synapses; Testing; Time; Translations; Two-Hybrid System Techniques; Voltage-Gated Potassium Channel; Work; Yeasts; cell growth regulation; immunoreactivity; in vivo; mouse model; mutant; novel therapeutics; protein function; protein protein interaction; research study; trafficking

DESCRIPTION (provided by applicant): The Slack and Slick genes encode Na+-activated K+ channels, which regulate the rate at which neurons adapt to maintained synaptic stimulation and the accuracy of timing of neuronal action potentials. These channels have also been proposed to play a key role in the protection of neurons and cardiomyocytes from hypoxic injury. In their general structure, they resemble other voltage-gated K channels, but have very large (>600 amino acid) intracellular C-termini. The C-terminal domain of Slack interacts with Fragile- X Mental Retardation protein (FMRP), an RNA-binding protein that regulates trafficking and translation of a subset of subset of neuronal mRNAs. The work in this application will use biochemical and electrophysiological assays to determine the specific regions of Slack and FMRP involved in their interactions both in vitro and in vivo, and will determine which specific regions are required for FMRP to control the gating of Slack channels. We shall also determine how the expression of Na+-activated K+ channels is altered in a mouse model of Fragile X syndrome (Fmr1-/-). In particular we shall determine the mechanism that in Fmr1-/- animals causes the total loss of expression of the distal C- terminus of Slack, a region that appears to be required for FMRP binding to the channels. Parallel electrophysiological and pharmacological experiments will evaluate the effects of this altered pattern of Slack expression on the functional properties of Na+- activated K+ channels in native neurons. An understanding of the biological properties and regulation of Slack and Slick channels will lead to a clearer understanding of the deficits in Fragile X syndrome and related disorders and is expected to lead to the development of novel therapeutic strategies. PUBLIC HEALTH RELEVANCE: Recent evidence suggests that activation of a relatively newly discovered class of proteins, termed sodium- activated potassium channels is regulated by their binding to Fragile X Mental Retardation Protein (FMRP). Inherited loss or deficits in FMRP are the leading cause of inherited intellectual disorders. The experiments in this application will determine the mechanisms and biological consequences of this channel-FMRP interaction. This information will be used to evaluate whether these channels are likely to be therapeutically useful drug targets, and in particular, whether pharmacological manipulations of sodium-activated potassium channels can overcome some of the impairments in neuronal activity that accompany loss of FMRP.

描述（由申请人提供）：Slack 和 Slick 基因编码 Na+ 激活的 K+ 通道，其调节神经元适应维持突触刺激的速率以及神经元动作电位计时的准确性。这些通道也被认为在保护神经元和心肌细胞免受缺氧损伤方面发挥着关键作用。在其一般结构中，它们类似于其他电压门控 K 通道，但具有非常大（> 600 个氨基酸）的细胞内 C 末端。 Slack 的 C 端结构域与脆性 X 精神发育迟滞蛋白 (FMRP) 相互作用，FMRP 是一种 RNA 结合蛋白，可调节神经元 mRNA 子集的运输和翻译。本申请的工作将使用生化和电生理学测定来确定 Slack 和 FMRP 参与体外和体内相互作用的特定区域，并将确定 FMRP 需要哪些特定区域来控制 Slack 通道的门控。我们还将确定脆性 X 综合征 (Fmr1-/-) 小鼠模型中 Na+ 激活的 K+ 通道的表达如何改变。特别是，我们将确定在 Fmr1-/- 动物中导致 Slack 远端 C 末端表达完全丧失的机制，该区域似乎是 FMRP 与通道结合所需的区域。平行的电生理学和药理学实验将评估 Slack 表达模式的改变对天然神经元中 Na+ 激活的 K+ 通道功能特性的影响。了解 Slack 和 Slick 通道的生物学特性和调节将有助于更清楚地了解脆性 X 综合征和相关疾病的缺陷，并有望促进新型治疗策略的开发。 公共健康相关性：最近的证据表明，一类相对较新发现的蛋白质（称为钠激活钾通道）的激活是通过其与脆性 X 智力迟钝蛋白 (FMRP) 的结合来调节的。 FMRP 的遗传性丧失或缺陷是遗传性智力障碍的主要原因。本应用中的实验将确定这种通道-FMRP 相互作用的机制和生物学后果。该信息将用于评估这些通道是否可能成为治疗上有用的药物靶点，特别是钠激活钾通道的药理学操作是否可以克服伴随 FMRP 丧失而导致的神经元活动损伤。