CNS L PROLINE TRANSPORTER

描述：(申请者摘要)哺乳动物，脑特异，高 亲和力L-脯氨酸转运蛋白(Prot)是Na和Pro基因家族中的一员 依赖CL的质膜转运蛋白，包括转运蛋白 几种神经递质、渗透激素和代谢物。这部小说 转运蛋白在推测为谷氨酸能的亚群中表达 神经元，在那里Prot蛋白在突触小泡中丰富。这些 研究结果证明PROT在突触前的调节作用值得考虑 在特定谷氨酸能神经末梢的兴奋性传递中。这个 这项研究的长期目标是阐明其生理作用 哺乳动物大脑中兴奋性突触传递的蛋白。具体目标1 将研究Prot在突触小泡中的功能作用。Prot是 唯一一种在分子水平上具有特异性的蛋白质 定位于兴奋性神经末梢的突触小泡。申请人 将免疫隔离含Prot的突触小泡并检查 这种独特的神经递质表型和生化特性 突触小泡的亚群。是含Prot的小泡吗 或谷氨酸能，或者它们代表了一组离散的 兴奋性神经末梢小泡具有前所未有的功能？一点儿 已知蛋白质是如何定位于突触小泡的。特定目标 2将使用重组DNA技术来识别可能的突触小泡 瞄准Prot中的信号。初步研究表明，初级 Prot的氨基酸序列包含靶向所需的信息 这种蛋白质到细胞内的小泡。最后，精密基板 尚未确定结合部位或此转运体的任何成员 一家人。最近的一些进展表明，PROT是一个很好的模型系统 以阐明转运蛋白的这一关键区域。特定目标 3将描绘底物结合结构域和/或易位孔 当然是Prot。这一发现可能为突触前调节提供新的见解 突触可塑性与兴奋性神经细胞的作用机制 损坏。

DESCRIPTION: (Applicant's abstract) The mammalian, brain-specific, high affinity L-proline transporter (PROT) is a member of a gene family of Na and Cl dependent plasma membrane transport proteins that includes transporters for several neurotransmitters, osmolytes, and metabolites. This novel transporter is expressed in subpopulations of putative glutamatergic neurons, where the PROT protein is enriched in synaptic vesicles. These findings warrant the consideration of a presynaptic regulatory role for PROT in excitatory transmission at specific glutamatergic nerve terminals. The long term objective of the research is to elucidate the physiological role of mammalian brain PROT in excitatory synaptic transmission. Specific aim 1 will investigate the functional role for PROT in synaptic vesicles. PROT is the only protein characterized at the molecular level that is specifically localized to synaptic vesicles in excitatory nerve terminals. The applicant will immunoisolate the PROT-containing synaptic vesicles and examine the neurotransmitter phenotype and biochemical properties of this unique subpopulation of synaptic vesicles. Are the PROT-containing vesicles prolinergic or glutamatergic, or do they represent a discrete set of excitatory nerve terminal vesicles with an unprecedented function? Little is known about how proteins are targeted to synaptic vesicles. Specific aim 2 will use recombinant DNA techniques to identify putative synaptic vesicle targeting signals in PROT. Preliminary studies indicate that the primary amino acid sequence of PROT contains information necessary for targeting this protein to intracellular vesicles. Finally, the precise substrate binding site has not been identified or any member of this transporter family. Several recent advances indicate that PROT is a good model system to elucidate this critical region of the transporter protein. Specific aim 3 will delineate the substrate binding domain and/or the translocation pore of PROT. The findings may provide new insights into presynaptic regulatory mechanisms involved in synaptic plasticity and excitotoxic nerve cell damage.