SIGNAL TRANSDUCTION BY CALCINEURIN IN T LYMPHOCYTES

T 淋巴细胞中钙调磷酸酶的信号转导

• 批准号: 6180715
• 负责人: Jun O. Liu
• 金额: $ 15.99万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至 2002-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6180715
• 关键词: T cell receptor; T lymphocyte; binding proteins; biological signal transduction; calcineurin; calcium; cyclic AMP; interleukin 2; leukocyte activation /transformation; molecular cloning; phorbols; phosphorylation; protein structure function; tissue /cell culture; transcription factor; yeast two hybrid system

DESCRIPTION: (Adapted from the investigator's abstract) The major goal of this proposal is to gain a molecular understanding of the mechanism of signal transduction by calcineurin during activation of T lymphocytes. The investigator has identified calcineurin as an important enzyme in the T cell receptor (TCR)-mediated signal transduction pathway leading to interleukin-2 (IL-2) production and as a common target for the immunosuppressive drugs cyclosporin A and FK506. Calcineurin is known to modulate the activities of at least three distinct classes of transcription factor including NF-AT, NF-kB and AP-1. However, many of the signaling molecules involved in the activation of NF-kB and AP-1 by calcineurin are not known. Calcineurin exists in multiple isoforms; it has been assumed that the a isoform of calcineurin mediates TCR signaling. Recently, calcineurin a was knocked out in mice, but no defect in the TCR-mediated IL-2 production was observed. In his preliminary studies, he has found that another isoform, calcineurin b, is more abundant than calcineurin a in T cells, suggesting that calcineurin b may play a dominant role in TCR signaling. Using FK506-resistant calcineurin mutants, he proposes to assess whether calcineurin b is sufficient to mediate TCR signaling. He will apply the yeast two-hybrid system to identify the substrates and associated proteins for calcineurin b to uncover signaling molecules involved in the activation of NF-kB and AP-1 by calcineurin. Alternatively, he will also employ catalytically inactive calcineurin mutants to identify calcineurin substrates from Jurkat cell extracts in vitro. Using partial cDNA sequences obtained from the yeast two-hybrid screen or oligopeptide sequences obtained from in vitro binding, the full length cDNA encoding putative calcineurin substrates and associated proteins will be cloned and further characterized in the context of TCR signaling. The identification of new signaling molecules through these studies will not only shed light on the molecular mechanism of TR signal transduction, but will also offer new targets for designing more specific and less toxic immunosuppressants.

描述：（改编自研究者的摘要）主要目标 这个提议是为了获得对机制的分子理解 T 淋巴细胞激活过程中钙调神经磷酸酶的信号转导。 这 研究人员已确定钙调神经磷酸酶是 T 细胞中的一种重要酶 受体 (TCR) 介导的信号转导通路导致白细胞介素 2 (IL-2) 的产生并作为免疫抑制药物的共同目标 环孢菌素A和FK506。 已知钙调神经磷酸酶可调节 至少三种不同类别的转录因子，包括 NF-AT， NF-kB 和 AP-1。 然而，许多信号分子参与 钙调神经磷酸酶对 NF-kB 和 AP-1 的激活尚不清楚。 钙调磷酸酶 存在多种异构体；假设 a 同工型 钙调神经磷酸酶介导 TCR 信号传导。 最近，钙调神经磷酸酶a被敲除 在小鼠中，但未观察到 TCR 介导的 IL-2 产生缺陷。 在 他的初步研究发现，另一种亚型，钙调神经磷酸酶 b， T 细胞中的钙调磷酸酶 a 含量更高，表明钙调磷酸酶 b可能在TCR信号传导中起主导作用。 采用耐FK506 钙调磷酸酶突变体，他建议评估钙调磷酸酶 b 是否是 足以介导 TCR 信号传导。 他将应用酵母二杂交 鉴定钙调神经磷酸酶 b 底物和相关蛋白的系统 揭示参与 NF-kB 和 AP-1 激活的信号分子 通过钙调神经磷酸酶。 或者，他还将采用催化非活性 钙调磷酸酶突变体用于鉴定 Jurkat 细胞中的钙调磷酸酶底物 体外提取物。 使用从酵母获得的部分 cDNA 序列 双杂交筛选或从体外结合获得的寡肽序列， 编码假定的钙调神经磷酸酶底物和相关的全长 cDNA 蛋白质将在 TCR 背景下被克隆并进一步表征 发信号。 通过这些识别新的信号分子 研究不仅将揭示TR信号的分子机制 转导，但也将为设计更具体的新目标提供新的目标 和毒性较小的免疫抑制剂。