Mechanisms of Vesicle Priming and Short-Term Plasticity

描述（由申请人提供）：在突触前释放钙离子依赖性神经递质之前，囊泡必须运输到活动区并启动融合能力状态。囊泡启动是决定突触传递效率和可塑性的关键过程之一。囊泡引发步骤的中心是由突触融合蛋白1、SNAP-25和小突触泡蛋白组成的突触三聚体SNARE蛋白复合物的受控组装。Syntaxin 1是唯一一种含有调节性的、推定的自抑制结构域的突触SNARE蛋白，并且认为在SNARE组装可以进行之前必须打开闭合的自抑制构象。基本引发因子Munc 13 -1和Munc 13 - 2的推定功能是催化这种构象变化。此外，Munc 13亚型可以动态调节小泡启动响应突触前活动。Munc 13 -1依赖性突触在动作电位序列期间抑制，而Munc 13 -2依赖性突触增强。该提案的目的是通过研究小鼠神经元的突触传递来功能分析突触融合蛋白1中构象开关的作用，所述小鼠神经元表达锁定在开放构象中的内源性突触融合蛋白1蛋白中的突变。第二，我们的目标是分析Munc 13功能的分子机制，通过系统分析的作用，Munc 13结构域在囊泡启动使用功能的拯救方法的增益。最后，我们将分析Munc 13亚型如何调节单个突触的短期可塑性，以及Munc 13依赖性抑制和增强如何控制中枢神经系统的信息流和突触可塑性。对这两个参与囊泡启动的关键分子的分子描述将有助于设计控制突触前功能的功效和可塑性的治疗药物。此外，详细了解神经递质释放的机制对于理解民族学和治疗神经系统疾病至关重要。

DESCRIPTION (provided by applicant): Before Ca 2+ dependent neurotransmitter release from the presynapse can be achieved, vesicle have to traffic to the active zone and prime to a fusion competent state. Vesicle priming is 1 of the key processes determining the efficiency of the synaptic transmission and plasticity. Central to the vesicle priming step is the controlled assembly of the synaptic trimeric SNARE protein complex consisting of Syntaxin 1, SNAP-25 and Synaptobrevin. Syntaxin 1 is the only synaptic SNARE protein that contains a regulatory, putative autoinhibitory domain, and it is thought that the closed, autoinhibitory conformation has to be opened before SNARE assembly can proceed. The putative function of the essential priming factors Munc13-1 and -2 is to catalyze this conformational change. In addition, Munc13 isoforms may dynamically regulate vesicle priming in response to presynaptic activity. Munc13-1 dependent synapses depress during trains of action potential, and Munc13-2 dependent synapses augment. The aims of this proposal is to functionally analyze the role of the conformational switch in Syntaxin 1 by studying synaptic transmission from murine neurons that express a mutation in the endogenous Syntaxin 1 protein locked in the open conformation. Second, we aim to analyze the molecular mechanism of Munc13 function by systematic analysis of the role of Munc13 domains in vesicle priming using a gain of function rescue approach. We will finally analyze how Munc13 isoforms regulate short-term plasticity in individual synapses, and how Munc13 dependent depression and augmentation control information flow and synaptic plasticity in the central nervous system. A molecular description of the the 2 key molecules involved in vesicle priming will aid the design of therapeutic drugs manipulating the efficacy and plasticity of presynaptic function. Moreover, a detailed knowledge of the mechanisms of neurotransmitter release is critical for the understanding of ethnology and treatment of neurological diseases.