IL-4-INDUCED SIGNAL TRANSDUCTION PATHWAYS IN HEMATOPOIETIC CELLS

IL-4 诱导的造血细胞信号转导途径

• 批准号: 5201560
• 负责人: J H PIERCE
• 金额: --
• 依托单位: DIVISION OF CANCER EPIDEMIOLOGY AND GENETICS
• 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/5201560
• 关键词: L cell; biological signal transduction; cytokine; cytokine receptors; enzyme substrate; hematopoietic stem cells; human tissue; insulin; insulin receptor; interleukin 2; interleukin 4; mitogens; molecular cloning; mutant; phosphoproteins; phosphorylation; protein purification; protein structure function; protein tyrosine kinase; receptor coupling; tissue /cell culture; transfection

Signal transduction mediated by insulin in nonhematopoietic cells was shown to be mediated by insulin receptor substrate-1 (IRS-1). IRS-1 can reconstitute mitogenic sensitivity to insulin or IL-4 in the 32D cell line, which does not express either IRS-1 or 4PS and is insensitive to IL-4 and insulin. Mutational analysis of IRS-1 was carried out to determine the regions that are important in mediated IL-4 or insulin- induced signaling in 32D cells. Point mutation at Tyr-895 within GRB2 binding site abolished GRB2-IRS-1 interaction with little or no effect on insulin-induced mitogenicity, suggesting that essential function of IRS-1 in proliferative signaling is largely unrelated to IRS-1-GRB-2 complex formation. A PH domain deletion mutant failed to undergo insulin-induced tyrosine phosphorylation, suggesting its role in receptor coupling. The most prominent tyrosine-phosphorylated substrate induced by IL-4 was a 170 kd (p170) protein, designated 4PS (IL-4-induced tyrosine-phosphorylated substrate). 4PS was purified and cloned from murine myeloid cell line, FDC-P2. Alignment of the 4PS sequence with IRS-1 revealed two distinct functional regions: a poorly conserved COOH- terminus with multiple common and unique tyrosine phosphorylation motifs, and a highly conserved NH-2-terminus containing a pleckstrin homology (PH) domain and phosphotyrosine binding (PTH) domain that mediates receptor coupling. Introduction of 4PS cDNA into 32D cells restored their mitogenic sensitivity to IL-4 and insulin. 4PS was redesignated IRS-2 due to its functional and structural similarities with IRS-1. IL- 13 is a recently described cytokine that displays many structural biological functions similar to IL-4. IL-13 induced a potent mitogenic response and prominent tyrosine phosphorylation of p170 in IL-3-dependent TF-1 cells. A series of analyses indicated that p170 was indeed 4PS/IRS- 2, the same substrate phosphorylated by IL-4. These results may provide a basis for their overlapping biological functions. Moreover, IL-13 and IL-4 both stimulated tyrosine phosphorylation of p170 in murine L cell fibroblasts. Enhanced phosphorylation of p170 was observed in response to IL-4, but not IL-13 treatment of L cells transfected with IL-2Rg. These results indicate that IL-13, unlike IL-4, does not utilize IL-2Rg in its receptor complex.

胰岛素介导的非造血细胞信号转导 显示由胰岛素受体底物-1（IRS-1）介导。 IRS-1可以 在32D细胞中重建对胰岛素或IL-4的促有丝分裂敏感性 线，不表达IRS-1或4PS，并且对 IL-4和胰岛素。 进行IRS-1的突变分析， 确定在介导的IL-4或胰岛素中重要的区域， 在32D细胞中诱导信号传导。 GRB 2内Tyr-895点突变 结合位点消除了GRB 2-IRS-1相互作用，几乎没有或没有影响 对胰岛素诱导的有丝分裂原性的影响，这表明 IRS-1在增殖信号传导中与IRS-1-GRB-2基本无关 复杂的形成。 一个PH结构域缺失突变体未能经历 胰岛素诱导酪氨酸磷酸化，提示其在受体 偶合器. 最突出的酪氨酸磷酸化底物诱导 IL-4诱导的p170蛋白表达量为170 kd，命名为4PS（IL-4诱导的 酪氨酸磷酸化底物）。 4PS是从 鼠骨髓细胞系FDC-P2。 4PS序列与 IRS-1揭示了两个不同的功能区域：一个保守性差的COOH- 末端具有多个共同和独特的酪氨酸磷酸化基序， 和一个高度保守的NH-2-末端，含有普列克底物蛋白同源性 (PH)结构域和磷酸酪氨酸结合（PTH）结构域， 受体偶联 将4PS cDNA导入恢复的32D细胞 它们对IL-4和胰岛素的促有丝分裂敏感性。 4PS重新命名 IRS-2与IRS-1的功能和结构相似。 白介素- 13是最近描述的细胞因子，其显示许多结构 与IL-4相似的生物学功能。 IL-13诱导了一种有效的促有丝分裂因子， IL-3依赖性细胞凋亡中p170的反应和显著的酪氨酸磷酸化 TF-1细胞。 一系列分析表明，p170确实是4PS/IRS-1。 2，由IL-4磷酸化的相同底物。 这些结果可以提供 这是它们重叠的生物学功能的基础。 此外，IL-13和 IL-4刺激小鼠L细胞p170酪氨酸磷酸化 成纤维细胞 p170的磷酸化增强， IL-2Rg转染的L细胞对IL-4的敏感性高于IL-13。 这些结果表明，IL-13与IL-4不同，不利用IL-2Rg 在它的受体复合物中。