The Neuronal alpha-bungarotoxin Binding Site

描述(申请人提供)：突触传递的中心是离子神经递质受体家族，负责神经和肌肉中对神经递质的快速反应。在这项提案中，将研究这一家族的一类受体，神经性尼古丁受体。作为尼古丁在大脑中的结合部位，这些受体对尼古丁成瘾负有责任，也可能在阿尔茨海默病等神经退行性疾病中发挥作用。神经元AChRs由许多不同的亚型组成，根据其不同的药理和分布进行分类。其中一个亚型，神经元a-银环蛇毒素结合受体(BgtR)将在这项资助中进行研究。我们发现BgtRs仅由烟碱型A7亚基组成，A7BgtRs的功能性表达仅发生在神经源性细胞中。第一个目标是确定和表征BgtR表达所需的神经元特异性处理。识别以神经元特异性方式调节BgtR表达的翻译后事件应该有助于深入了解其他受体和通道是如何调控的。另一个目的是确定BgtRs上BGT结合位点的数量，并开始表征BgtR抗体的多肽结合位点。AB肽在阿尔茨海默病的发病中起着关键作用，它与BgtR结合，改变BgtR功能，并触发神经元内第二信使的变化。要检验的假设是：1)A7亚单位棕榈酰化是表达功能性BgtR所需的一系列加工事件之一；2)每个BgtR上有四个配体结合部位，这些部位可以根据拮抗剂的不同亲和力来区分；以及3)抗体多肽结合到BgtR细胞外表面不同于配体结合部位的位置。

DESCRIPTION (provided by applicant): Central to synaptic transmission are the family of ionotropic neurotransmitter receptors, which are responsible for the rapid responses to neurotransmitters in nerve and muscle. In this proposal, a class of receptors that are members of this family, the neuronal nicotinic receptors, will be studied. As the site where nicotine binds in the brain, these receptors are responsible for nicotine addiction and may also play a role in neurodegenerative diseases such as Alzheimer's disease. Neuronal AChRs are composed of a number of subtypes as classified by their diverse pharmacology and distribution. One such subtype, the neuronal a-bungarotoxin binding receptor (BgtR) will be studied in this grant. We have found that that BgtRs are composed only of nicotinic a7 subunits and functional expression of a7 BgtRs only occurs in cells of neuronal origin. The first objective is to identify and characterize the neuronal-specific processing required for BgtR expression. The identification of posttranslational events that regulate BgtR expression in a neuronal-specific manner should provide insights into how other receptors and channels are regulated. The other objective is to determine the number of Bgt binding sites on BgtRs and to begin to characterize the BgtR Ab peptide binding sites. Ab peptides, which are play a critical role in the onset of Alzheimer's disease, bind to BgtRs, altering BgtR function and trigger second messenger changes within neurons. The hypotheses to be tested are that: 1) a7 subunit palmitoylation is one of a series of processing events required for expression of functional BgtRs; 2) there are four ligand binding sites on each BgtR and the sites can be distinguished by different affinities for antagonists; and 3) Ab peptides bind to a site on the BgtR extracellular surface different from the ligand binding sites.