Control of NF-AT Signaling Through Nuclear Import

描述（由申请人提供）：NF-AT转录因子是关键 T细胞活化的钙信号通路中的效应物， 肌肉发育和突触可塑性。一般认为， 四种NF-AT在静息细胞中位于细胞质中，但被触发进入细胞核 并通过钙调磷酸酶（一种钙激活磷酸酶）反式激活基因。最近 然而，数据正在推翻NF-AT模型的一些假设， 为管理这只手臂的复杂调节机制提供了新的见解， 钙信号传导。例如，小鼠基因敲除四种NF-AT， 同种型已经得出了意想不到的结论，即NFAT 1和NF-AT 4在 事实上，负调节T细胞活化，而只有NF-AT 2似乎， 对细胞因子基因具有预测的阳性活性。这些数据 特别有趣的是，T细胞、肌细胞和神经元似乎 同时表达多种NF-AT同种型，表明激活必须 取决于这些因素的不同调节。我们现在已经开始 通过评估所有四种NE-AT同种型的动力学来解决这个问题， 钙信号传导和细胞环境的功能。值得注意的是，这些 数据揭示了显着程度的NE-AT同种型依赖动力学，并建议 细胞类型和钙非依赖性途径对 最终的NF-AT反应。因此，我们假设这些NF-AT家族 成员必须有区别地受到监管途径， 扩展那些由钙信号传递，并了解这些 替代机制对于预测细胞功能依赖于 在NF-AT上 这是一个建议，以揭示机制的差异NE-AT信号， 牢房我们将（1），确定潜在的生化信号通路 差异NE-AT调节及其程度;（2）阐明 钙非依赖性途径，通过高度保守的激活 在所有四种NE-AT中保守的机制;（3），通过 差分调制NE-AT动态的高通量光学屏幕 NE-AT同种型;和（4），使用这些小分子功能性剖析 NE-AT同种型对复杂过程如T 细胞激活我们预计，这种新的评估NE-AT活动， 将直接为自身免疫性疾病提供更特异的治疗方法， 器官移植和心肌病

DESCRIPTION (provided by applicant): The NF-AT transcription factors are key effectors in the calcium signaling pathways underlying T cell activation, muscle development, and synaptic plasticity. It is generally thought that the four NF-ATs are cytoplasmic in resting cells but triggered to enter the nucleus and transactivate genes by calcineurin, a calciumactivated phosphatase. Recent data, however, are overturning some of the assumptions of the NF-AT model and offering new insights to the complex regulatory mechanisms governing this arm of calcium signaling. For instance, mouse gene knockouts of the four NF-AT isotypes have rendered the unexpected conclusion that NFAT1 and NF-AT4 are in fact negative regulators of T cell activation, while only NF-AT2 appears to have the predicted positive activity towards cytokine genes. These data are especially interesting because T cells, myocytes, and neurons appear to simultaneously express multiple NF-AT isotypes, indicating that activation must depend on the differential regulation of these factors. We have now begun to address this problem by evaluating the dynamics of all four NE-AT isotypes as a function of calcium signaling and cellular environment. Significantly, these data reveal a remarkable degree of NE-AT isotype-dependent dynamics and suggest important contributions of cell type and calcium-independent pathways to the ultimate NF-AT response. We hypothesize, therefore, that these NF-AT family members must be differentially subject to regulatory pathways that override or extend those imparted by calcium signaling, and that understanding these alternative mechanisms is essential for predicting cellular functions dependent on NF-ATs. This is a proposal to uncover the mechanisms of differential NE-AT signaling in the cell. We will (1), determine the biochemical signaling pathways underlying differential NE-AT regulation and their extent; (2) elucidate the calcium-independent pathways that operate through a highly conserved activation mechanism conserved in all four NE-ATs; (3), identify small molecules through high-throughput optical screens of NE-AT dynamics which differentially modulate the NE-AT isotypes; and (4), use these small molecules to functionally dissect the individual contributions of NE-AT isotypes to complex processes such as T cell activation. We anticipate that this novel evaluation of NE-AT activity will directly contribute to more specific therapies for autoimmune disease, organ transplantation, and cardiomyopathies.