CNS L PROLINE TRANSPORTER

描述：（申请人的摘要）哺乳动物，脑特异性，高表达。 亲和L-脯氨酸转运蛋白（PROT）是Na基因家族的成员， 包括转运蛋白的Cl依赖性质膜转运蛋白 几种神经递质渗透调节剂和代谢物 这本小说 转运蛋白在假定的谷氨酸能受体亚群中表达， 神经元，其中PROT蛋白在突触囊泡中富集。 这些 研究结果证明了PROT在突触前的调节作用 在兴奋性传递中的作用。 的 这项研究的长期目标是阐明 哺乳动物大脑PROT在兴奋性突触传递中的作用。 具体目标1 将研究PROT在突触囊泡中的功能作用。 PROT是 唯一一种在分子水平上 定位于兴奋性神经末梢的突触囊泡。 申请人 将免疫隔离含有PROT的突触囊泡，并检查 这种独特的神经递质表型和生化特性 突触囊泡的亚群。 含有蛋白质的囊泡 脯氨酸能的或谷氨酸能的，还是它们代表了一组离散的 兴奋性神经末梢囊泡具有前所未有的功能 小 蛋白质是如何定位于突触囊泡的。 具体目标 2将使用重组DNA技术来鉴定推定的突触囊泡 PROT中的目标信号。 初步研究表明， PROT的氨基酸序列包含靶向所必需的信息 这种蛋白质的细胞内囊泡。 最后，精确的基底 尚未确定结合位点或该转运蛋白的任何成员 家人 最近的一些进展表明，PROT是一个很好的模型系统 来阐明这个转运蛋白的关键区域 具体目标 3将描绘底物结合结构域和/或易位孔 的PROT。 这些发现可能为突触前调节提供新的见解 突触可塑性和兴奋性神经细胞的机制 损害

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.