Il2 Receptors--molecular Regulation

人类白细胞介素-2受体正在研究中，以了解正常和肿瘤细胞中T细胞免疫应答的关键成分。T细胞活化后，IL-2和IL-2受体被诱导; T细胞免疫应答的幅度和持续时间由产生的IL-2的量、表达的受体水平和这些事件的时间过程控制。存在IL-2受体的三条链，IL-2 Ra、IL-2 Rb和gc，其中IL-2 Ra和IL-2 Rb在转录水平上受到显著调节。该小组主要关注IL-2诱导的信号类型，特别是STAT蛋白（信号转导和转录激活因子）的激活，以及它们调节IL-2 Ra基因的机制。Stat 5a和Stat 5 b是两种密切相关的蛋白质，具有>90%的氨基酸同一性，由IL-2激活。一个问题是这些密切相关的蛋白质的作用是否是多余的或独特的。为了试图澄清这个问题，已经产生了Stat 5a和Stat 5 b转基因小鼠来重建敲除小鼠。此外，除了先前报道的IL-2 Ra基因5'调控区中的IL-2应答元件之外，还报道了另一个重要的调控元件，称为PRRIV。该元件在人类和小鼠中高度保守，位于第一内含子中。该元件由Stat 5和HMG-I（Y）蛋白调节。与上游IL-2应答元件一起，内含子元件控制IL-2介导的IL-2 Ra基因的调节。在一项合作研究中，还报道了HTLV-1 p12 I蛋白可以增强Stat 5活化并减少原代人外周血单核细胞增殖的IL-2需求。总之，这些研究大大增强了我们对IL-2 R表达和Stat 5依赖性基因调控基础的理解。

The human interleukin-2 receptor is being studied to understand critical components of the T cell immune response in normal and neoplastic cells. Following T-cell activation, IL-2 and IL-2 receptors are induced; the magnitude and duration of the T-cell immune response is controlled by the amount of IL-2 produced, the levels of receptors expressed, and the time course of these events. Three chains of the IL-2 receptor exist, IL-2Ra, IL-2Rb, and gc, with IL-2Ra and IL-2Rb being significantly regulated at the level of transcription. The group has focused primarily on the types of signals induced by IL-2, particularly the activation of STAT proteins (signal transducers and activators of transcription), and the mechanism by which they regulate the IL-2Ra gene. Stat5a and Stat5b are two closely related proteins with >90% amino acid identity that are activated by IL-2. An issue is whether these closely related proteins are redundant or distinctive in their actions. To attempt to clarify this issue, Stat5a and Stat5b transgenic mice have been generated to reconstitute the knockout mice. Moreover, in addition to a previously reported IL-2 response element in the 5' regulatory region of the IL-2Ra gene, the existence of another important regulatory element, denoted PRRIV, was reported. This element is highly conserved in humans and mice and is located in the first intron. This element is regulated by Stat5 and HMG-I(Y) proteins. Together with the upstream IL-2 response element, the intronic element controls IL-2-mediated regulation of the IL-2Ra gene. In a collaborative study, it was also reported that the HTLV-1 p12I protein can enhance Stat5 activation and diminish the IL-2 requirement for proliferation of primary human peripheral blood mononuclear cells. Together, these studies substantially enhance our understanding of the basis of IL-2R expression and Stat5-dependent gene regulation.