Analysis of the mechanism intracellularly transmitting the reception signal of insulin in cultured adipocytes and hepatoma cells.

培养脂肪细胞和肝癌细胞细胞内传递胰岛素接收信号的机制分析。

• 批准号: 60560088
• 负责人: KITAGAWA Yasuo
• 金额: $ 1.28万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1985
• 资助国家: 日本
• 起止时间: 1985 至 1986
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60560088/
• 关键词: Insulin; Tyrosine-specific protein phosphrylating activity; Insulin receptor; Urea cycle enzyme; Hepatoma cells; 3T3-L1 cells; 肥満

Insulin ragulates a variety of cell functions by binding to a specific receptor embedded in plasma membrane. Insulin-receptor is composed of <alpha> and <beta> -subunits. <alpha> -subunit is responsible for the binding and <beta> -subunit has protein kinase activity which is specific to tyrosine-residue. By the binding of insulin to receptor complex, auto-phosphorylation of <beta> -subunit has been demonstrated. However, it is controversial whether this auto-phosphorylation is the prime step for transmitting the signal of insulin binding. In addition to the auto-phosphorylation, phosphorylation of plasma membrane proteins or cytoskeleton proteins has been observed depending on insulin and it is not clear which phosphorylation is the most important.Various cellular functions have been demonstrated to be regulated by insulin. These include 1) transport of nutrients, such as sugars and amino acids, is stimulated by insulin, 2) anabolism of carbohydrates, lipids and amino acids is stimulated by insulin, and 3) proliferation of many cells in culture is stimulated by insulin. Considering such a variety of effects, it is more reasonable to assume many signal-transmitting mechanisms by which insulin regulate cellular functions.In order to find out better experimental systems to analyze the signal-transmitting mechanism of insulin, regulation of the expression of carbamoyl-phosphate synthetase gene (a urea cycle enzyme) in hepatoma cells and in primary cultured hepatocytes was studied. Supression of the gene expression of a urea cycle enzyme by insulin was demonstrated for the first time. A multiple-regulation of a urea cycle enzyme by glucocorticoids, glucagon and catecholamines was found. Effect of factors including insulin on the adipose conversion of 3T3-L1 was also analyzed. By this analysis, an important progress was made concerning the regulation of obesity.

胰岛素通过与质膜上的特异性受体结合来调节细胞的多种功能。胰岛素受体由α和β<alpha><beta>亚基组成。<alpha>- 亚基负责结合，<beta>-亚基具有对酪氨酸残基特异的蛋白激酶活性。通过胰岛素与受体复合物的结合，证明了β-亚基的自磷酸化<beta>。然而，这种自磷酸化是否是传递胰岛素结合信号的主要步骤是有争议的。除了自身磷酸化外，还观察到依赖于胰岛素的质膜蛋白或细胞骨架蛋白的磷酸化，但不清楚哪种磷酸化是最重要的。这些包括1）营养物如糖和氨基酸的运输受胰岛素刺激，2）碳水化合物、脂质和氨基酸的转运受胰岛素刺激，以及3）培养物中许多细胞的增殖受胰岛素刺激。考虑到胰岛素对细胞功能的多种作用，我们认为胰岛素调节细胞功能的信号传递机制是多种多样的，为了寻找更好的实验系统来分析胰岛素的信号传递机制，我们研究了氨甲酰磷酸合成酶（一种尿素循环酶）基因在肝癌细胞和原代培养肝细胞中的表达调控。首次证实胰岛素可抑制尿素循环酶的基因表达。糖皮质激素、胰高血糖素和儿茶酚胺对3 T3-L1的尿素循环酶具有多重调节作用，并分析了胰岛素等因素对3 T3-L1脂肪转化的影响。通过这种分析，在肥胖的调控方面取得了重要进展。

项目成果

Y.Aratani;E.Sugimoto;Y.Kitagawa: FEBS Letters. (1987)

Y.Aratani；E.Sugimoto；Y.Kitakawa：FEBS 信件。

Y.Kitagawa, E.Sugimoto: "Interaction between glucocorticoids, 8-bromoadenosine 3',5'-monophosphate and insulin in regulation of carbamoyl-phosphate synthetase I synthesis in Reuber hepatoma H-35." Eur. J. Biochem.150. 249-254 (1985)

Y.Kitakawa、E.Sugimoto：“糖皮质激素、8-溴腺苷 3,5-单磷酸和胰岛素之间的相互作用在调节 Reuber 肝癌 H-35 中氨基甲酰磷酸合成酶 I 的合成中。”

Y.Kitagawa, J.Ryall, M.Nguyen, G.C.Shore: "Expression of carbamoyl-phosphate synthetase I mRNA in Reuber hepatoma H-35. Regulation by glucocorticoid and insulin." Biochim. Biophys. Acta. 825. 148-153 (1985)

Y.Kitakawa、J.Ryall、M.Nguyen、G.C.Shore：“Reuber 肝癌 H-35 中氨基甲酰磷酸合成酶 I mRNA 的表达。糖皮质激素和胰岛素的调节。”

Y.Aratani., E.Sugimoto, Y.Kitagawa: "Lithium ion reversibly inhibits inducer-stimulated adipose conversion of 3T3-L1." FEBS Letters. (1987)

Y.Aratani.、E.Sugimoto、Y.Kitakawa：“锂离子可逆地抑制诱导剂刺激的 3T3-L1 脂肪转化。”

Y.Kitagawa;E.Sugimoto: Eur.J.Biochem.,. 150. 249-254 (1985)

Y.北川；E.杉本：Eur.J.Biochem.，。