Cyclic AMP- and Ca2+-Signaling in Sensory Transduction by Olfactory Receptor Neurons

嗅觉受体神经元感觉转导中的环 AMP 和 Ca2 信号传导

• 批准号: 9173025
• 负责人: KING-WAI YAU
• 金额: $ 34.43万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-12-01 至 2020-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9173025
• 关键词: Address; Adenylate Cyclase; Animals; Binding; Biochemical; Cations; Cilia; Complement; Confusion; Cyclic AMP; Cyclic Nucleotides; Defect; Detection; Disease; Dissection; Feedback; Foundations; G-substrate; GTP-Binding Protein alpha Subunits, Gs; Gene Targeting; Genetic; Genotype; Goals; Golf; Hand; Investigation; Kinetics; Label; Laboratories; Lead; Mass Spectrum Analysis; Mediating; Mus; Mutation; Nose; Odorant Receptors; Olfactory Epithelium; Olfactory Receptor Neurons; Pathway interactions; Phenotype; Phototransduction; Physiological; Population; Process; Proteins; Protocols documentation; Rana; Retinal Cone; Role; Sensitivity and Specificity; Sensory; Signal Transduction; Smell Perception; Stimulus; Suction; Time; Uncertainty; Ursidae Family; Vertebrates; Vision; Western Blotting; Work; experimental study; insight; olfactory bulb; olfactory threshold; patch clamp; public health relevance; response; retinal rods; success

 DESCRIPTION (provided by applicant): The long-term objective of this proposal is to understand in quantitative detail the cAMP- and Ca2+-signaling in sensory transduction by olfactory receptor neurons (ORNs). We shall focus on the question of canonical olfactory-transduction mechanism in ORNs of the vertebrate main olfactory epithelium. The major chemo-transduction mechanism in ORNs of the main olfactory epithelium involves a cAMP-signaling cascade, leading to Na+ and Ca2+ influxes through a cyclic-nucleotide-gated (CNG), non-selective cation channel to depolarize the ORN to firing threshold. The Ca2+ influx leads to signal amplification via a Ca2+-activated Cl channel, as well as olfactory adaptation via multiple Ca2+-activated negative-feedback pathways. Recently, the significance of these amplification and negative-feedback pathways is nonetheless thrown into doubt and confusion. We propose to refine and quantify our understanding of the transduction process and to resolve the confusion surrounding the signal amplification and negative feedbacks. In Aim 1, we shall characterize the ORNs from the M71-monoclonal-nose mouse line, with the objective of using it as the common genetic background for many of the experiments in this proposal. This genotype offers the distinct advantage of having a near-homogeneous population of ORNs in the main olfactory epithelium, making experimental investigations much more efficient, and, in some cases, exclusively possible. In Aim 2, the objective is to carry out a detailed dissection, in both amplitude and time, of the overall ORN olfactory response into its CNG and Cl- current components for determining their correlations in amplitude and kinetics. In Aim 3, our goal is to re-examine the hypothesis that the Ca2+-mediated signal amplification via the Ca2+-activated Cl- current dictates the stimulus threshold for odorant detection. In Aim 4, our objective is to resolve the mystery/confusion about the relevance of the Ca2+-mediated negative feedbacks in olfactory transduction. Elucidating the steps of olfactory transduction will provide great insight into olfactory malfunctions arising from genetic defects in the transduction pathway, as amply demonstrated by the huge success in the case of vision.

 描述（由适用提供）：该提案的长期目标是在定量的详细信息中了解嗅觉受体神经元（ORNS）的感觉翻译中的cAMP和CA2+信号。我们将重点介绍脊椎动物主嗅觉上皮的ORN中的规范嗅觉转移机制。主要嗅觉上皮的ORN中的主要化学转导机制涉及营地信号的级联反应，从而通过环核苷酸门控（CNG），非选择性阳离子通道导致Na+和Ca2+的影响，以将ORN定义为ORN至射击阈值。 Ca2+的影响会通过CA2+激活的CL通道以及通过多个CA2+激活的负反馈途径进行嗅觉适应性进行信号扩增。最近，这些放大和负反馈途径的意义仍然引起了疑问和困惑。我们建议完善和量化我们对翻译过程的理解，并解决围绕信号放大和负面反馈的混乱。在AIM 1中，我们将表征来自M71单克荷兰小鼠系的ORN，目的是将其用作本提案中许多实验的常见遗传背景。该基因型具有明显的优势，即在主要嗅觉上皮中拥有几乎均匀的ORN群体，从而使实验研究更加有效，在某些情况下，完全可能。在AIM 2中，目的是在两者中进行详细的解剖 整体ORN嗅觉响应对其CNG和CL-电流组件的总体ORN嗅觉响应的放大器和时间，用于确定其在放大器和动力学中的相关性。在AIM 3中，我们的目标是重新检查以下假设：Ca2+通过Ca2+活化的CL循环进行了CA2+介导的信号扩增决定了气味检测的刺激阈值。在AIM 4中，我们的目标是解决有关嗅觉翻译中CA2+介导的负反馈相关性的神秘/混乱。阐明嗅觉翻译的步骤将提供对转移途径中遗传缺陷引起的嗅觉故障的深入了解，这是由于视觉而言巨大的成功所证明的。