Characterization of Human Trace Amine Receptors

描述（由申请人提供）：微量胺是生物源性非儿茶酚胺单胺，以低浓度存在于脊椎动物神经系统中。一些微量胺，如章鱼胺和酪胺，在无脊椎动物的神经系统中含量更丰富，它们作为神经递质的功能已经相当完善。哺乳动物中枢神经系统中微量胺的分布不均、代谢迅速，以及微量胺受体的存在，提示某些微量胺在哺乳动物中枢神经系统中也可能是神经递质或共递质。这一建议利用了最近鉴定和分子克隆的DNA家族的微量胺受体（TARs）。有趣的是，TARs聚集在人类6号染色体（6q23）的一个区域，许多研究表明该区域与精神分裂症有关。微量胺在神经精神疾病中的作用已被提出，而TARS也是许多滥用药物的作用位点。这些发现提出了一种假设，即其中一种TARs的多态性会改变蛋白质的功能，从而导致精神分裂症症状和/或药物滥用。作为评估这一假设的第一步，我们提出以下具体目标：在促进其在细胞表面表达的条件下，每个TAR都会在哺乳动物细胞中稳定表达。要测试的三种策略是对受体进行基因修饰，使用潜在的配体作为“药物伴侣”，以及抑制受体内化。2. TARs的激动剂和拮抗剂将通过测试潜在的单胺配体刺激或抑制环AMP积累的能力，以及在稳定表达受体亚型的哺乳动物细胞中激活有丝分裂原激活的蛋白激酶的能力来确定。3. 具有非同义snp的TAR变异将在哺乳动物细胞中稳定表达，以确定多态性对细胞表面表达、配体结合和受体功能的影响。这些研究的理想结果是确定所有编码全长受体的TAR在细胞表面表达的条件，确定每种TAR亚型的激动剂和拮抗剂，并确定改变TAR亚型功能或配体结合的等位基因变异

DESCRIPTION (provided by applicant): Trace amines are biogenic non-catecholamine monoamines that are present at low concentrations in the vertebrate nervous system. Some trace amines, such as octopamine and tyramine, are more abundant in invertebrate nervous systems, where their function as neurotransmitters is fairly well established. The heterogeneous CNS distribution and rapid turnover of trace amines, together with the existence of trace amine receptors, suggest that some trace amines may also be neurotransmitters or co-transmitters in the mammalian CNS. This proposal takes advantage of the recent identification and molecular cloning of the DNA for a family of trace amine receptors (TARs). Interestingly, the TARs are clustered in a region of human chromosome 6 (6q23) where linkage to schizophrenia has been suggested by a number of studies. A role for trace amines in neuropsychiatric disorders has been proposed, and the TARS are also sites of action for many abused drugs. These findings suggest the hypothesis that a polymorphism in one of the TARs changes the function of the protein and thus contributes to the symptoms of schizophrenia and/or to drug abuse. As an initial step towards evaluating this hypothesis we propose the following specific aims: 1. Each TAR will be stably expressed in mammalian cells under conditions that promote its expression on the cell surface. Three strategies to be tested are genetic modification of the receptors, the use of potential ligands as "pharmacological chaperones", and inhibition of receptor internalization. 2. Agonists and antagonists for the TARs will be identified by testing the ability of potential monoamine ligands to stimulate or inhibit cyclic AMP accumulation and to activate mitogen-activated protein kinases in mammalian cells stably expressing the receptor subtypes. 3. TAR variants with non-synonymous SNPs will be stably expressed in mammalian cells to determine the effect of the polymorphism on cell surface expression, ligand binding, and function of the receptor. The ideal outcome of these studies would be to identify conditions under which all TARs encoding full-length receptors are expressed on the cell surface, to identify agonists and antagonists for each TAR subtype, and to identify allelic variants that alter the function or ligand binding of a TAR subtype