SIGNAL TRANSDUCTION BY CALCINEURIN IN T LYMPHOCYTES

描述：（改编自研究者摘要） 这个提议是为了从分子水平上了解 T淋巴细胞活化过程中钙调磷酸酶信号转导。 的 研究者已经确定钙调神经磷酸酶是T细胞中的一种重要酶 受体（TCR）介导的信号转导途径导致白细胞介素-2 （IL-2）的产生和作为免疫抑制药物的共同靶点 环孢菌素A和FK506。 已知钙调神经磷酸酶调节 至少三类不同的转录因子，包括NF-AT， NF-κ B和AP-1。 然而，许多参与细胞凋亡的信号分子， 钙调磷酸酶对NF-κ B和AP-1的激活作用尚不清楚。 钙调 存在于多种亚型中;已经假定， 钙调磷酸酶介导TCR信号传导。 最近，钙调神经磷酸酶a被敲除， 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， 在T细胞中比钙调神经磷酸酶a更丰富，这表明钙调神经磷酸酶 B可能在TCR信号转导中起主导作用。 使用FK506抗性 钙调神经磷酸酶突变体，他建议评估钙调神经磷酸酶B是否 足以介导TCR信号传导。 他将应用酵母双杂交技术 鉴定钙调磷酸酶B的底物和相关蛋白的系统 揭示参与NF-κ B和AP-1激活的信号分子 钙调磷酸酶 或者，他还将使用催化惰性的 从Jurkat细胞鉴定钙调磷酸酶底物的钙调磷酸酶突变体 体外提取物。 使用从酵母中获得的部分cDNA序列， 双杂交筛选或从体外结合获得的寡肽序列， 全长cDNA编码推定的钙调磷酸酶底物和相关的 蛋白质将被克隆并在TCR的背景下进一步表征 发信号。 通过这些新的信号分子的鉴定 研究不仅将揭示TR信号的分子机制， 转导，但也将提供新的目标，设计更具体的 和毒性更低的免疫抑制剂。

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.