PRESYNAPTIC CALCIUM CHANNELS & CYSTEINE STRING PROTEINS

突触前钙通道

• 批准号: 3418827
• 负责人: JOY A UMBACH
• 金额: $ 10.87万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-07-27 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3418827
• 关键词: CHO cells; Drosophilidae; Xenopus oocyte; calcium channel; calcium flux; cysteine; electrophysiology; gene expression; gene mutation; insect poison; ionomycin; molecular cloning; neural conduction; neural transmission; neurotransmitter transport; protein structure function; synapses; voltage /patch clamp; voltage gated channel

Presynaptic calcium channels are vital elements that regulate communication at virtually all chemical synapses. Only in the last couple of years has investigation of these channels advanced to the molecular level. In this context, an important contribution has been the recent cloning by this group of a novel protein, CCCS1, that is essential for the normal operation of presynaptic calcium channels in Torpedo (fish). CCCS1 is either an integral subunit or regulator of these channels. Interestingly, database searches revealed that CCCS1 homologs of undetermined function had previously been cloned in Drosophila. These proteins, call cysteine-string proteins (csps), had been identified using monoclonal antibodies and were concentrated at Drosophila nerve terminal membranes. Preliminary results (obtained in collaboration with the discoverers of the Csp gene) indicate that deletions at the csp locus lead to defects in neuromuscular transmission that can be traced to a dysfunction of nerve ending calcium channels. The goal of this proposal is to confirm and extend these dramatic results. First CCCS1 and the csps will be co-expressed with other calcium channel subunits in frog oocytes or cultured mammalian cells. Electrophysiological characteristics of the calcium currents of these cells will give insights into the molecular interactions of these proteins. Second, a comprehensive investigation will be made of synaptic transmission in Drosophila csp mutants versus rescued and wild type controls. This will refine our understanding of the cellular consequences attending presynaptic defects in calcium channels and the csps. Third, calcium channels of the cell bodies of neurons from mutant and control flies will be studied by patch clamp to determine if there are alterations of channel properties that may help to understand csp function. Taken together, these experiments lay the foundation for a wide range of new approaches to study presynaptic activity. Moreover, it can hardly escape attention that the severely afflicted csp mutants (which barely survive to adulthood even when reared at 16-18 degrees C) may be useful models for congenital neurological diseases. And, ultimately one can hope that investigations of this new family of cysteine-string proteins will have beneficial ramifications for learning and memory disorders, mental retardation, myasthenic syndromes and other disorders of the synapse.

突触前钙通道是调节的重要元素 几乎所有化学突触的通讯。 仅在最后 几年来，对这些渠道的调查已进展到 分子水平。 在此背景下，一项重要贡献是 该组最近克隆了一种新的蛋白质 CCCS1，这是必不可少的 鱼雷突触前钙通道的正常运行 （鱼）。 CCCS1 是这些的一个完整子单元或调节器 渠道。 有趣的是，数据库搜索显示 CCCS1 同源物 之前已在果蝇中克隆了未确定功能的功能。 这些 蛋白质，称为半胱氨酸串蛋白（csps），已被鉴定为 单克隆抗体并集中在果蝇神经末梢 膜。 初步结果（与 Csp 基因的发现者）表明 csp 位点的缺失 导致神经肌肉传递缺陷，可以追溯到 神经末梢钙通道功能障碍。 本提案的目标 是为了确认并扩展这些戏剧性的结果。 首先是 CCCS1 和 csps 将与青蛙中的其他钙通道亚基共表达 卵母细胞或培养的哺乳动物细胞。 电生理学 这些细胞的钙电流特征将给出 深入了解这些蛋白质的分子相互作用。 第二，一个 将对突触传递进行全面研究 果蝇 csp 突变体与拯救和野生型对照。 这将 完善我们对细胞后果的理解 钙通道和 csps 的突触前缺陷。 三、补钙 突变体和对照果蝇神经元细胞体的通道将 通过膜片钳研究以确定是否存在改变 通道属性可能有助于理解 csp 功能。 采取 这些实验共同为一系列新的研究奠定了基础 研究突触前活动的方法。 而且，也很难逃脱 请注意，遭受严重影响的 csp 突变体（几乎无法生存） 即使在 16-18 摄氏度下饲养到成年）也可能是有用的模型 用于先天性神经系统疾病。 并且，最终人们可以希望 对这个新的半胱氨酸串蛋白家族的研究将有 对学习和记忆障碍、精神障碍等有益的影响 发育迟缓、肌无力综合征和其他突触疾病。