Spatiotemporal activation and actions of Munc13 in neurotransmitter release

Munc13 在神经递质释放中的时空激活和作用

• 批准号: 8530052
• 负责人: Victor A Cazares
• 金额: $ 3.31万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-05 至 2015-09-04
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8530052
• 关键词: Action Potentials; Address; Affect; Alzheimer' s Disease; Amyloid beta-Protein Precursor; Basic Science; Characteristics; Cognition; Cognitive; Cognitive deficits; Complex; Coupling; Dementia; Disease; Fluorescence Resonance Energy Transfer; Frequencies; Future; Glean; Goals; Health; Human; Image; Intercellular Junctions; Investigation; Knowledge; Learning; Link; Measurement; Mediating; Memory; Mental Depression; Molecular; Monitor; Nervous system structure; Neurodegenerative Disorders; Neurons; Optics; Patients; Pattern; Pharmaceutical Preparations; Physiological; Probability; Process; Property; Proteins; Recruitment Activity; Regulation; Reporter; Role; SNAP receptor; Senile Plaques; Signal Pathway; Signal Transduction; Site; Subcellular Spaces; Substance abuse problem; Synapses; Synaptic Transmission; Synaptic plasticity; System; Techniques; Testing; Tissues; Vesicle; Work; age related; amyloid peptide; fluorescence imaging; genetic manipulation; information processing; insight; molecular dynamics; monomer; motor learning; nervous system disorder; neural circuit; neurotransmission; neurotransmitter release; novel; postsynaptic; presynaptic; relating to nervous system; spatiotemporal; transmission process; voltage

DESCRIPTION (provided by applicant): Transmission of information through neural circuits required for cognition, learning, and motor function occurs via Ca2+-dependent release of neurotransmitters and their reception by postsynaptic neurons at specialized junctions termed synapses. Neurons commonly use a broad bandwidth of action potential frequencies to encode information, which together with a limited number of neurotransmitter release sites requires that synaptic release be highly tunable. Munc13-1 is a presynaptic protein essential for excitatory neurotransmitter release and a central determinant of release rates. Specifically, Munc13-1 transitions vesicles into a readily releasable state, and thus regulates enhancement or depression of synapses. Importantly, recent evidence suggests that the activation state of Munc13-1 is itself precisely regulated, perhaps by RIM proteins, which facilitate transition of Munc13-1 from an auto-inhibited homodimer to a vesicular priming active monomer. The objective of this proposal is to elucidate the molecular dynamics by which Munc13-1 is transitioned into its priming-active state in addition to determining the functional significance of Munc13-1's interaction with RIM for activation and priming. To address this we capitalize of a novel technique, TIRF/FRET that can monitor the temporal and spatial characteristics of Munc13-1 transitions from autoinhibitory homodimers to physiologically active monomers. Furthermore, using a combination of genetic manipulations, fluorescence imaging, and electrophysiological measurements we will delineate: 1) the temporal and spatial properties of Munc13- 1 activation and 2) the molecular mechanism by which RIM enhances Munc13-1-mediated neurotransmitter release. From these studies we expect to develop an understanding of Munc13-1 activation and regulation for vesicle priming, as well as reveal the features of the Munc13-1/RIM interaction important for coupling Ca2+ signaling and priming to enhance neurotransmitter release. Uncovering the dynamics of how Munc13-1 may impact presynaptic plasticity will provide insights into mechanisms by which synapses are modified to sustain complex information processing. The information sought is fundamentally important to human health, as Munc13-1 is central to neurotransmission & synaptic plasticity. In fact, many neurological diseases and age-related deficits in cognitive ability are tightly linked to deficits in synaptic transmission. Moreover, Munc13 mediated vesicle priming has been shown to regulate the amyloid precursor protein which gives rise to senile plaques composed of 2-amyloid peptides characteristic of neural tissue in Alzheimer's disease patients. Thus, the importance of understanding Munc13 dynamics goes beyond basic science discovery and will serve future studies focused on identifying causes and drug treatments for dementia.

描述（由申请人提供）：认知、学习和运动功能所需的神经回路的信息传输是通过 Ca2+ 依赖性神经递质的释放以及突触后神经元在称为突触的特殊连接处的接收来实现的。神经元通常使用宽带宽的动作电位频率来编码信息，这与有限数量的神经递质释放位点一起要求突触释放高度可调。 Munc13-1 是一种突触前蛋白，对于兴奋性神经递质释放至关重要，也是释放速率的核心决定因素。具体而言，Munc13-1 将囊泡转变为易于释放的状态，从而调节突触的增强或抑制。重要的是，最近的证据表明，Munc13-1 的激活状态本身可能受到 RIM 蛋白的精确调节，这有助于 Munc13-1 从自动抑制的同二聚体转变为囊泡引发活性单体。该提案的目的是阐明 Munc13-1 转变为引发活性状态的分子动力学，以及确定 Munc13-1 与 RIM 相互作用对于激活和引发的功能意义。为了解决这个问题，我们利用了一种新技术 TIRF/FRET，它可以监测 Munc13-1 从自抑制同型二聚体到生理活性单体转变的时间和空间特征。此外，结合使用遗传操作、荧光成像和电生理测量，我们将描述：1）Munc13-1 激活的时间和空间特性；2）RIM 增强 Munc13-1 介导的神经递质释放的分子机制。通过这些研究，我们希望加深对 Munc13-1 激活和囊泡启动调节的了解，并揭示 Munc13-1/RIM 相互作用的特征，这对于耦合 Ca2+ 信号传导和启动以增强神经递质释放至关重要。揭示 Munc13-1 如何影响突触前可塑性的动态将有助于深入了解突触被修改以维持复杂信息处理的机制。所寻求的信息对人类健康至关重要，因为 Munc13-1 对于神经传递和突触可塑性至关重要。事实上，许多神经系统疾病和与年龄相关的认知能力缺陷与突触传递缺陷密切相关。此外，Munc13介导的囊泡引发已被证明可以调节淀粉样前体蛋白，该蛋白在阿尔茨海默病患者的神经组织中产生由2-淀粉样肽组成的老年斑。因此，了解 Munc13 动力学的重要性超出了基础科学发现的范围，并将服务于未来的研究，重点是确定痴呆症的病因和药物治疗。