Waldmann T, Tagaya Y, Bamford R
Metabolism Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Int Rev Immunol. 1998;16(3-4):205-26. doi: 10.3109/08830189809042995.
Both IL-15 and IL-2 are 14-15 kDa members of the four alpha-helical bundle family of cytokines that have T cell growth factor activity. In contrast to the pattern manifested by IL-2, IL-15 mRNA is produced by a wide variety of tissues other than T cells. We have demonstrated that IL-15 expression is posttranscriptionally regulated by multiple elements, including the ten upstream AUGs of the 5' UTR, a 48aa signal peptide and the carboxy-terminus of the mature protein. IL-15 utilizes two distinct receptor signaling pathways. In T cells the IL-15 receptor includes IL-2R beta and gamma c subunits shared with IL-2 as well as an IL-15 specific receptor, IL-15R alpha. However, mast cells respond to IL-15 using a receptor system that does not share elements with the IL-2R system but involves a novel 60-65 kDa IL-15RX subunit. In mast cells, IL-15 signaling involves JAK-2 and STAT-5 activation rather than the JAK-1 and JAK-3 as well as the STAT-3 and STAT-5 used by both IL-2 and IL-15 in activated T cells.
IL-15和IL-2都是细胞因子的四α螺旋束家族中具有T细胞生长因子活性的14 - 15 kDa成员。与IL-2所表现出的模式不同，IL-15 mRNA由T细胞以外的多种组织产生。我们已经证明，IL-15的表达受到多种元件的转录后调控，包括5' UTR的十个上游AUG、一个48aa信号肽和成熟蛋白的羧基末端。IL-15利用两种不同的受体信号通路。在T细胞中，IL-15受体包括与IL-2共享的IL-2Rβ和γc亚基以及一个IL-15特异性受体IL-15Rα。然而，肥大细胞对IL-15的反应使用的受体系统与IL-2R系统没有共同元件，而是涉及一个新的60 - 65 kDa的IL-15RX亚基。在肥大细胞中，IL-15信号传导涉及JAK-2和STAT-5的激活，而不是IL-2和IL-15在活化T细胞中使用的JAK-1和JAK-3以及STAT-3和STAT-5。
