Membrane Trafficking of Vesicular Monoamine Transporter

突触传递依赖于神经递质的有效包装 变成专门的分泌囊泡。对于在体内合成的单胺 细胞质，这种包装需要主动运输通过囊泡膜。 干扰囊泡胺转运的药物具有很强的精神性 影响，表明这项活动在精神疾病中的重要性。 有趣的是，单胺储存在两个不同的分泌囊中： 突触小泡(SVS)和大致密核心小泡(LDCV)。SVS快速调停 突触传递，而LDCV具有神经调节作用。鉴于 特定的转运活动定义了分泌囊泡的含量， 运输蛋白在不同囊泡上的定位将决定 单胺释放的方式和地点。这项提议的长期目标是 了解神经递质储存和释放的变化如何影响 突触传递，因此行为。策略是研究排序 将单胺打包成不同的分泌物的运输蛋白 水泡。以PC-12细胞为模型系统，我们发现囊泡 单胺转运体(VMATs)优先定位于LDCV，而 亲缘关系密切的囊泡乙酰胆碱转运体(VAChT)，优先于 SVS.我们将在本提案中重点研究神经元VMAT2的作用机制 参与VMAT2到LDCV的分类，具体目标如下：1) 研究VMAT2分选分泌小泡的途径。2)至 确定以VMAT2到LDCV为目标的排序序列。3)识别 调节VMAT2分类的相互作用的蛋白质。拟议的研究将 确定途径、排序序列和参与其中的调节蛋白 神经内分泌细胞和神经元中VMAT2对分泌小泡的分选。 这些信息将有助于我们理解单胺类药物是如何 神经传递在储存和释放水平上受到调节。这部作品 也将允许我们在未来从基因上改变VMAT2的本地化 并确定单胺从体内释放的生物学意义 LDCV和SVS，这可能会导致更好地理解功能 受胺能通路的调节，如那些潜在的药物寻求和 精神病患者的行为。

Synaptic transmission depends on the efficient packaging of neurotransmitters into specialized secretory vesicles. For monoamines that are synthesized in the cytoplasm, this package requires active transport across the vesicle membrane. Drugs that interfere with vesicular amine transport have profound psychotropic effects, indicating the importance of this activity in psychiatric diseases. Interestingly, monoamines are stored in two distinct secretory vesicles: synaptic vesicles (SVs) and large dense core vesicles (LDCVs). SVs mediate fast synaptic transmission, while LDCVs have a neuromodulatory role. Whereas the specific transport activity defines the content of secretory vesicles, the localization of the transport protein on distinct vesicles will determine the mode and site of monoamine release. The long-term objective of this proposal is to understand how changes in neurotransmitter storage and release influence synaptic transmission, and hence behavior. The strategy is to study the sorting of the transport proteins that package monoamines into distinct secretory vesicles. Using PC 12 cells as a model system, we have found that vesicular monoamine transporters (VMATs) preferentially localize to LDCVs whereas the close related vesicular acetylcholine transporter (VAChT), preferentially to SVs. We will focus on neuronal VMAT2 in this proposal to explore the mechanisms involved in the sorting of VMAT2 to LDCVs with the following Specific Aims: 1) To examine the routes by which VMAT2 sorts to secretory vesicles. 2) To identify the sorting sequences that target VMAT2 to LDCVs. 3) To identify interacting proteins that regulate VMAT2 sorting. The proposed studies will identify the routes, sorting sequences, and the regulatory proteins involved in the sorting of VMAT2 to secretory vesicles in neuroendocrine cells and neurons. This information will facilitate our understanding of how the monoaminergic neural transmission is regulated at the level of storage and release. This work will also allow us in the future to genetically alter the localization of VMAT2 in vivo and determine the biological significance of monoamine release from LDCVs as well as SVs, which could lead to better understanding of the functions regulated by aminergic pathways, such as those underlying drug seeking and psychotic behaviors.