REGULATION OF HORMONE-RESPONSIVE ADENYLATE CYCLASE

激素反应性腺苷酸环化酶的调节

• 批准号: 3881722
• 负责人: P H FISHMAN
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3881722
• 关键词: G protein; adenylate cyclase; affinity chromatography; biological signal transduction; cyclic AMP; dopamine receptor; hormone regulation /control mechanism; human tissue; inhibitor /antagonist; laboratory rat; muscarinic receptor; neoplastic cell; neoplastic cell culture for noncancer research; neuroblastoma; neuropeptide Y; neuropeptide receptor; phosphatidylinositols; radiotracer; receptor binding; receptor sensitivity; stimulant /agonist; synapses

Neuropeptide Y (NPY) binds to Y1-subtype receptors on MC-IXC cells and to Y2 receptors on SMS-MSN, two human neuroblastoma cell lines. NPY inhibits adenylate cyclase in MC-IXC but not SMS-MSN cells. NPY binding in both cell lines is inhibited by pertussis toxin, which ADP-ribosylates 4l kDalton G proteins in both. Western blotting with specific antibodies to G-alpha subunits showed that MC-IX has Gi(alpha), the inhibitory G protein of adenylate cyclase whereas SMS-MSN has both Gi(alpha) and Go(alpha), which has been implicated in activation of ion channels. Thus, Y1 receptors appear to mediate inhibition of adenylate cyclase and Y2, activation of ion channels. In contrast to other beta-adrenergic responsive cell lines which have beta2-adrenergic receptors (beta 2 AR), SK-N-MC have beta1 AR and undergo an unusual desensitization when exposed to agonists. There is no loss of B1 AR or maximum agonist-stimulated adenylate cyclase activity but a shift in the dose response which can be mimicked by incubating membranes with ATP and the catalytic subunit of cyclic AMP-dependent protein kinase (PKA). Desensitization is blocked in permeable cells by a specific inhibitor of PKA but not an inhibitor of beta AR kinase. A large-scale purification of the dopamine D1 receptor from rat striatum has been carried out and the purified receptor is being used to obtain peptide sequences, antibodies, and eventually the receptor gene. The latter will be useful for identifying defects in the receptor that occur in disease states. In kidney, D1 receptors coupled to adenylate cyclase have been implicated in regulation of sodium transport. Dopamine fails to stimulate adenylate cyclase in proximal convoluted tubules from spontaneous hypertensive rats although the enzyme responds normally to other effectors. As the binding activity and apparent molecular weight of the kidney receptors from the hypertensive rats are normal, it appears that the D1 receptors are defective in their ability to couple to the stimulatory G protein of adenylate cyclase.

神经肽 Y (NPY) 与 MC-IXC 细胞上的 Y1 亚型受体结合并 SMS-MSN（两种人神经母细胞瘤细胞系）上的 Y2 受体。 NPY抑制 MC-IXC 细胞中存在腺苷酸环化酶，但 SMS-MSN 细胞中不存在腺苷酸环化酶。两个细胞中的 NPY 结合 百日咳毒素可抑制百日咳毒素，该毒素可将 ADP 核糖基化 4l kDalton G 两者中都有蛋白质。使用 G-α 特异性抗体进行蛋白质印迹 亚基显示 MC-IX 具有 Gi(α)，即抑制性 G 蛋白 腺苷酸环化酶，而 SMS-MSN 同时具有 Gi(α) 和 Go(α)，这 与离子通道的激活有关。因此，Y1受体 似乎介导腺苷酸环化酶和 Y2 的抑制、离子的激活 渠道。与其他 β-肾上腺素能反应细胞系相比， 具有 β2 肾上腺素能受体 (β 2 AR)，SK-N-MC 具有 β1 AR 和 当暴露于激动剂时会经历不寻常的脱敏。没有 B1 AR 或最大激动剂刺激的腺苷酸环化酶活性丧失，但 剂量反应的变化可以通过孵化膜来模拟 与 ATP 和环 AMP 依赖性蛋白激酶的催化亚基 （PKA）。通透细胞中的脱敏作用被特定的物质阻断 PKA 抑制剂，但不是 β AR 激酶抑制剂。一个大规模的 从大鼠纹状体中纯化多巴胺 D1 受体 纯化的受体被用来获得肽序列， 抗体，最终是受体基因。后者将有助于 识别疾病状态下发生的受体缺陷。在 在肾脏中，与腺苷酸环化酶偶联的 D1 受体与 钠转运的调节。多巴胺不能刺激腺苷酸 自发性高血压大鼠近曲小管环化酶 尽管酶对其他效应器反应正常。作为绑定 肾受体的活性和表观分子量 高血压大鼠是正常的，看来D1受体是 与刺激性 G 蛋白偶联的能力有缺陷 腺苷酸环化酶。