From the Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611.
J Biol Chem. 2013 Nov 15;288(46):33272-82. doi: 10.1074/jbc.M113.493171. Epub 2013 Oct 7.
The inositol-requiring enzyme 1α (IRE1α) is a serine-threonine kinase that plays crucial roles in activating the unfolded protein response. Studies suggest that IRE1α is activated during thymic T cell development and in effector CD8(+) T cells. However, its role in regulating T helper cell differentiation remains unknown. We find that IRE1α is up-regulated and activated upon CD4(+) T cell activation and plays an important role in promoting cytokine IL-4 production. CD4(+) T cells from IRE1α KO mice have reduced IL-4 protein expression, and this impaired IL-4 production is not due to the altered expression of Th2 lineage-specific transcription factors, such as GATA3. Instead, IL-4 mRNA stability is reduced in IRE1α KO T cells. Furthermore, treatment of T cells with an IRE1α-specific inhibitor, 4μ8C, leads to a block in IL-4, IL-5, and IL-13 production, confirming the role of IRE1α in the regulation of IL-4. This study identifies a regulatory function for IRE1α in the promotion of IL-4 in T cells.
肌醇需求酶 1α(IRE1α)是一种丝氨酸/苏氨酸激酶,在激活未折叠蛋白反应中发挥关键作用。研究表明,IRE1α 在胸腺 T 细胞发育和效应 CD8(+)T 细胞中被激活。然而,其在调节辅助性 T 细胞分化中的作用尚不清楚。我们发现,IRE1α 在 CD4(+)T 细胞激活时上调并被激活,并在促进细胞因子 IL-4 产生中发挥重要作用。IRE1α KO 小鼠的 CD4(+)T 细胞中 IL-4 蛋白表达减少,这种 IL-4 产生受损不是由于 Th2 谱系特异性转录因子(如 GATA3)的表达改变所致。相反,IRE1α KO T 细胞中 IL-4 mRNA 的稳定性降低。此外,用 IRE1α 特异性抑制剂 4μ8C 处理 T 细胞会导致 IL-4、IL-5 和 IL-13 的产生受阻,证实了 IRE1α 在调节 IL-4 中的作用。这项研究确定了 IRE1α 在 T 细胞中促进 IL-4 产生中的调节功能。