Molecular Mechanisms of Vesicular Glutamate Transport

描述（由申请人提供）：本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如何影响神经元损伤。突触传递是神经元特异性的细胞间通讯的主要机制，需要将神经递质集中到突触囊泡中以促进其快速和精确的释放。最近，负责兴奋性神经递质谷氨酸在突触囊泡中的储存的蛋白质已经被鉴定。然而，这些蛋白质（VGLUT1和VGLUT2）发挥功能的基本机制仍然不确定。数据表明，VGLUT1也可以转运磷酸盐，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储存，因此重要的是要清楚地表征VGLUT1在这些过程中发挥的作用的性质。为解决这些问题，提出了三个目标。该提议的第一个目的是确定VGLUT 1催化突触囊泡中谷氨酸积累的机制。第二个目的是确定VGLUT1除了将谷氨酸转运到囊泡中之外，是否还充当磷酸盐转运或氯离子通道。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。这些目标的进展将导致更好地了解囊泡谷氨酸转运的潜在分子机制，并深入了解VGLUT 1在囊泡储存谷氨酸，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.