Molecular Mechanisms of Vesicular Glutamate Transport

描述(由申请人提供)：这项提案的广泛长期目标是定义参与大脑信息处理调节的机制，以及这些机制可能如何影响神经元损伤。突触传递是神经元细胞间通讯的主要机制，需要神经递质集中到突触小泡中，以促进其快速和准确的释放。最近，负责在突触小泡中储存兴奋性神经递质谷氨酸的蛋白质被鉴定出来。然而，这些蛋白质(VGLUT1和VGLUT2)的基本功能机制仍不清楚。数据表明，VGLUT1也可能运输磷酸盐，并作为氯离子通道发挥作用。由于这些额外的功能将影响囊泡谷氨酸的储存，因此清楚地描述VGLUT1在这些过程中所起作用的性质是很重要的。为了解决这些问题，我们提出了三个目标。这项建议的第一个目的是确定VGLUT1催化谷氨酸在突触小泡中积累的机制。第二个目的是确定VGLUT1除了将谷氨酸运输到囊泡外，是否还起到磷酸盐运输或氯离子通道的作用。第三个目的是确定VGLUT1的二级结构以及结构与蛋白质功能的关系。这些目标的进展将有助于更好地理解囊泡谷氨酸运输的潜在分子机制，并深入了解VGLUT1在囊泡谷氨酸储存、突触传递和兴奋性毒性中的作用。

DESCRIPTION (provided by applicant): The broad long-term goal of this proposal is to define mechanisms involved in the regulation of information processing in the brain and how these mechanisms may impact on neuronal injury. Synaptic transmission, the major neuron specific mechanism for cell-to-cell communication, requires the concentration of neurotransmitters into synaptic vesicles to facilitate their rapid and precise release. Recently, the proteins responsible for the storage of the excitatory neurotransmitter glutamate in synaptic vesicles have been identified. However, the basic mechanisms by which these proteins (VGLUT1 and VGLUT2) function remain undetermined. Data suggests that VGLUT1 may also transport phosphate and function as a chloride channel. Since these additional functions will influence vesicular glutamate storage, it is important to clearly characterize the nature of the role that VGLUT1 plays in these processes. Three Aims are proposed to address these issues. The first Aim of this proposal is to define mechanism by which VGLUT1 catalyzes the accumulation of glutamate in synaptic vesicles. The second Aim is to determine if, in addition to transporting glutamate into vesicles, VGLUT1 also functions as a phosphate transport or chloride channel. The third Aim is to determine the secondary structure of VGLUT1 and the relationship of the structure to the functions of the protein. Progress in these Aims will lead to an improved understanding of the underlying molecular mechanisms of vesicular glutamate transport and insight into the role of VGLUT1 in vesicular storage of glutamate, synaptic transmission and excitotoxicity.