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）：通过认知，学习和运动功能所需的神经回路传播信息，这是通过Ca2+依赖性释放神经递质的释放及其在称为突触的专用连接处通过突触后神经元接受的。神经元通常使用广泛的动作潜在频率进行编码信息，这些信息与有限数量的神经递质释放位点一起，要求突触释放高度调节。 MUNC13-1是一种突触前蛋白，对于兴奋性神经递质释放必不可少，也是释放速率的中心决定因素。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郁。重要的是，最近的证据表明，Munc13-1的激活状态本身就是通过RIM蛋白的精确调节，这可能是促进Munc13-1从自动抑制同二聚体向水泡启动活性单体的过渡。该建议的目的是阐明Munc13-1通过确定Munc13-1与RIM进行激活和启动的RIM相互作用的功能意义之外，通过将Munc13-1转换为启动活性状态的分子动力学。为了解决这个问题，我们利用了一种新型技术，可以监测从自身抑制同型二聚体到生理活性单体的MUNC13-1过渡的时间和空间特征的TIRF/FRET。此外，使用遗传操作，荧光成像和电生理测量的组合，我们将描述：1）Munc13-1激活的时间和空间特性和2）RIM增强MUNC13-1介导的神经递质的释放。从这些研究中，我们期望对囊泡启动的Munc13-1激活和调节有所了解，并揭示Munc13-1/RIM相互作用的特征，对于耦合Ca2+信号传导和启动至关重要，以增强神经递质的释放。揭示Munc13-1如何影响突触前可塑性的动力学将提供有关修改突触以维持复杂信息处理的机制的见解。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。实际上，认知能力的许多神经系统疾病和与年龄相关的缺陷与突触传播的缺陷紧密相关。此外，已显示Munc13介导的囊泡启动可以调节淀粉样蛋白前体蛋白，从而导致老年症患者中神经组织的2-淀粉样蛋白肽的衰老斑块。因此，了解Munc13动力学的重要性超出了基础科学的发现，并将为未来的研究提供侧重于识别痴呆症的原因和药物治疗的研究。