Dynamic Regulation of Neurotransmitter Release

描述（由申请人提供）：阐明突触可塑性的分子基础将导致对神经回路修饰的更复杂理解，神经回路修饰是健康和疾病中经验依赖可塑性的基础。关于突触后形式的持久可塑性的机制，我们知道的很多。然而，相比之下，人们对突触前可塑性的机制知之甚少。本研究的重点是了解一类突触前活性区蛋白（RIMs）的突触功能，因为它们是突触前LTP的重要形式，并且在基础神经递质释放和短期可塑性中起着额外的作用。rim有几个蛋白质结合域，与突触囊泡和活跃区的关键成分相互作用。正因为如此，rim被描述为突触前“支架”蛋白。作为一种支架，RIM是了解几种重要的突触前蛋白的协调活动的有力工具。一个关键的突出问题是了解RIM如何整合其结合伙伴的活动来实现突触可塑性。在本提案中，我们将在RIM1a敲除背景下进行拯救实验，以描述RIM1a与其他突触前蛋白相互作用的功能意义。我们还将研究介导LTP的关键PKA磷酸化位点的功能意义。最后，我们将评价RIM2基因产物的功能意义。它们在功能上是冗余的，还是特定RIM异构体的表达传达了不同的突触特性？为了进行这些实验，我们将在培养和急性切片制备中使用电生理记录技术，并结合分子技术将基因转移到敲除背景中。准确理解突触前可塑性背后的分子相互作用，对于研究突触前可塑性的行为意义，以及针对这些蛋白开发治疗多种可能涉及突触可塑性的神经精神疾病（如痴呆、肌张力障碍和成瘾）至关重要。

DESCRIPTION (provided by applicant): Elucidating the molecular basis of synaptic plasticity will lead to a more sophisticated understanding of the neural circuit modifications which underlie experience-dependent plasticity in both health and disease. Much is known about the mechanisms of postsynaptic forms of long lasting plasticity. By comparison, however, relatively little is known about the mechanisms of presynaptic plasticity. This proposal focuses on understanding the synaptic functions of a class of presynaptic, active zone proteins, RIMs, because of their requirement in a prominent form of presynaptic LTP and their additional roles in basal neurotransmitter release and short-term plasticity. RIMs have several protein binding domains that interact with key components of synaptic vesicles and active zones. Because of this, RIMs have been described as presynaptic "scaffold" proteins. As a scaffold, RIM is a powerful tool to gain insight to the coordinate activities of several important presynaptic proteins. A key outstanding question is to understand how RIM integrates the activities of its binding partners to achieve synaptic plasticity. In this proposal, we will perform rescue experiments in the RIM1a knockout background to delineate the functional significance of RIM1a's interactions with other presynaptic proteins. We will also study the functional significance of a key PKA phosphorylation site that is implicated in mediating LTP. Lastly, we will evaluate the functional significance of the RIM2 gene products. Are they functionally redundant or does expression of a particular RIM isoform convey distinct synaptic properties? To perform these experiments we will use electrophysiological recording techniques on both culture and acute slice preparations in combination with molecular techniques to allow gene transfer into the knockout background. A precise understanding of the molecular interactions that underlie presynaptic plasticity as described in this proposal is critical both to enable studies of the behavioral significance of presynaptic plasticity and to enable targeting these proteins for the development of therapies for a wide range of neuropsychiatric diseases that may involve synaptic plasticity such as dementia, dystonia and addiction.