Analysis of Ca2+ -Triggered Neurotransmitter Release

Ca2 触发神经递质释放的分析

• 批准号: 7259427
• 负责人: CHRISTIAN ROSENMUND
• 金额: $ 29.6万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2010-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7259427
• 关键词: Action Potentials; Address; Affinity; Attention; Autistic Disorder; Binding; Biochemical; Brain; C2 Domain; Cell membrane; Chromosome Pairing; Communication; Complex; Dependency; Disease; Dominant-Negative Mutation; Family member; Finding by Cause; Generic Drugs; Genetic; Goals; Helix (Snails); In Vitro; Individual; Knockout Mice; Light; Mediating; Membrane; Membrane Fusion; Molecular; Mus; Mutate; Mutation; N-terminal; Neurons; Neurotransmitters; Pattern; Penetration; Phenotype; Phospholipids; Physiological; Process; Property; Protein Family; Protein Overexpression; Proteins; Purpose; Rate; Reaction; Research Personnel; Role; SNAP receptor; Schizophrenia; Screening procedure; Shapes; Signal Transduction; Speed; Structure-Activity Relationship; Synapses; Synaptic Transmission; Tertiary Protein Structure; Testing; Time; Transducers; Translating; Vesicle; Viral; base; complement C2a; complement C2b; coping; deficit syndrome; design; ear helix; gain of function; insight; loss of function; millisecond; mutant; neurotransmission; neurotransmitter release; programs; reconstitution; research study; response; synaptotagmin; synaptotagmin I; synaptotagmin VII

DESCRIPTION (provided by applicant): Efficient and rapid transduction mechanisms at synapses are required for coherent oscillations and synchronization of activity of brain circuits. The presynapse transduces within <1 ms action potentials into a Ca2+-triggered synchronous fusion of neurotransmitter containing vesicles. Two protein families, the Complexins and Synaptotagmins, are key players in tuning the generic SNARE protein-based membrane fusion apparatus into a high speed transducer. Both proteins are known to interact with the SNARE complex. The goal of this study is to understand how these proteins accomplish fast fusion, and to determine which interactions are relevant for their function. We hypothesize that Complexin and Synaptotagmin 1 act by reducing the energy barrier of the fusion reaction, but they accomplish this using different molecular mechanisms. Following binding to the SNARE complex, Complexins seem to cause stabilization of a profusion complex, or alternatively, serve as an adaptor to enable Synaptotagmin 1 binding to the SNARE complex. Synaptotagmin 1 may trigger fast neurotransmitter release by Ca2+-dependent binding of its C2A and C2B domains to the plasma membrane, and this membrane penetration determines fusion rates by destabilizing the profusion membrane complex. To decipher the function of Complexin and Synaptotagmin, we propose an integrated approach using electrophysiological, structural, and biochemical experiments. First, we will analyze synaptic properties in neurons derived from Complexin 1/2/Synaptotagmin 1 knockout mice. We will then explore the structure-function relationship of protein domains that are putatively involved in synchronous release using a rescue approach. Finally, we will probe whether both proteins act independently or in conjunction with each other, and whether they act sequentially. A better understanding of the mechanism of synchronous release may help to find the cause and treatment of diseases that show disturbed oscillations and synchronization patterns in brain circuits, like Attention Deficit Syndrome, Autism, Huntingdon's Disease or Schizophrenia.

描述(由申请人提供)：有效和快速的突触转导机制是一致振荡和大脑回路活动同步所必需的。突触前在1毫秒的动作电位内转换为钙离子触发的含有囊泡的神经递质的同步融合。两个蛋白质家族，络合素和突触素，是将通用的基于SNARE蛋白的膜融合装置调整为高速传感器的关键角色。已知这两种蛋白质都与SNARE复合体相互作用。这项研究的目标是了解这些蛋白质是如何完成快速融合的，并确定哪些相互作用与它们的功能相关。我们假设复合素和突触素1通过降低融合反应的能垒来发挥作用，但它们使用不同的分子机制来实现这一点。在与SNARE复合体结合后，Complexins似乎可以稳定一个丰富的复合体，或者作为一个适配器，使synaptopagmin 1能够与SNARE复合体结合。突触素1可以通过依赖于钙离子的C2a和C2b结构域与质膜的结合来触发神经递质的快速释放，这种膜穿透通过破坏融合膜复合体的稳定性来决定融合率。为了破译复杂蛋白和突触素的功能，我们提出了一种综合的方法，使用电生理、结构和生化实验。首先，我们将分析复杂蛋白1/2/突触素1基因敲除小鼠神经元的突触特性。然后，我们将探索蛋白质结构域的结构-功能关系，这些结构域可能参与了使用救援性方法的同步释放。最后，我们将探讨这两种蛋白质是独立发挥作用还是相互联合作用，以及它们是否按顺序发挥作用。更好地理解同步释放的机制，可能有助于找到大脑回路中表现出紊乱的振荡和同步模式的疾病的原因和治疗，如注意力缺陷综合症、自闭症、亨廷顿病或精神分裂症。