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: 8339180
• 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/8339180
• 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钙离子依赖的神经递质的释放和突触后神经元在称为突触的特殊连接上的接收而发生的。神经元通常使用宽频带的动作电位频率来编码信息，再加上有限数量的神经递质释放部位，要求突触释放是高度可调的。Munc13-1是一种突触前蛋白，对兴奋性神经递质的释放是必不可少的，也是释放速率的中心决定因素。具体地说，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的激活状态本身受到精确调控，可能受RIM蛋白的调控，RIM蛋白促进Munc13-1从自动抑制的同源二聚体转变为囊泡启动活性单体。本研究的目的是阐明Munc13-1转变为启动活性状态的分子动力学，并确定Munc13-1‘S与RIM相互作用在激活和启动中的功能意义。为了解决这个问题，我们利用了一种新的技术，TIRF/FRET，它可以监测Munc13-1从自抑制性同源二聚体到生理活性单体的时间和空间特征。此外，结合遗传操作、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促进Munc13-1介导的神经递质释放的分子机制。通过这些研究，我们希望了解Munc13-1对囊泡启动的激活和调节，并揭示Munc13-1/RIM相互作用的特征，该相互作用对于耦合钙信号和启动以促进神经递质释放具有重要意义。揭示Munc13-1如何影响突触前可塑性的动力学将为突触被修饰以维持复杂信息处理的机制提供洞察力。所寻求的信息对人类健康至关重要，因为Munc13-1是神经传递和突触可塑性的核心。事实上，许多神经系统疾病和与年龄相关的认知能力缺陷都与突触传递障碍密切相关。此外，Munc13介导的囊泡启动已被证明调节淀粉样前体蛋白，该蛋白导致阿尔茨海默病患者神经组织特有的2-淀粉样多肽组成的老年斑。因此，了解Munc13动力学的重要性超越了基础科学发现，并将服务于未来专注于确定痴呆症病因和药物治疗的研究。