Habib Tania, Senadheera Shantha, Weinberg Kenneth, Kaushansky Kenneth
Division of Hematology, University of Washington School of Medicine, Seattle, Washington 98195, USA.
Biochemistry. 2002 Jul 9;41(27):8725-31. doi: 10.1021/bi0202023.
The common cytokine receptor gamma chain (gamma c), an essential component of the receptors for IL-2, IL-4, IL-7, IL-9, and IL-15, is critical for the development and function of lymphocytes. Recently, a novel lymphokine (IL-21) and its receptor (IL-21R alpha) were described which profoundly affect the growth and activation state of B, T, and NK cells in concert with other lymphokines or stimuli [Parrish-Novak, J., et al. (2000) Nature 408, 57-63]. In this report, we show that gamma c is also a required signaling component of the IL-21 receptor (IL-21R) using the gamma c-deficient X-linked severe combined immunodeficiency (XSCID) lymphoblastoid cell line JT, and JT cells reconstituted with gamma c (JT/gamma c). Moreover, we demonstrate a functional requirement for both gamma c and the gamma c-associated Janus family tyrosine kinase 3 (JAK3) in IL-21-induced proliferation of pro-B-lymphoid cells engineered to express human IL-21R alpha (BaF3/IL-21R alpha). Retroviral-mediated transduction of wild-type gamma c into XSCID JT cells restored function to the IL-21R, as shown by IL-21-induced tyrosine phosphorylation of JAK1 and JAK3, and downstream activation of STAT5, in JT/gamma c cells as well as BaF3/IL-21R alpha and primary splenic B cells. In contrast, IL-21 failed to activate the JAK-STAT pathway in nonreconstituted JT cells. Monoclonal antibodies specific for the gamma c chain effectively inhibited IL-21-induced growth of BaF3/IL-21R alpha cells, supporting a functional role for this molecule in the IL-21R complex. In addition, the specific JAK3 tyrosine kinase inhibitor WHI-P131 significantly reduced IL-21-induced proliferation of BaF3/IL-21R alpha cells. Taken together, these results definitively demonstrate that IL-21-mediated signaling requires the gamma c chain, and indicate that JAK3 is an essential transducer of gamma c-dependent survival and/or mitogenic signals induced by this cytokine.
常见细胞因子受体γ链（γc）是白细胞介素-2（IL-2）、IL-4、IL-7、IL-9和IL-15受体的重要组成部分，对淋巴细胞的发育和功能至关重要。最近，一种新型淋巴因子（IL-21）及其受体（IL-21Rα）被发现，它们与其他淋巴因子或刺激物协同作用，深刻影响B细胞、T细胞和自然杀伤（NK）细胞的生长和激活状态[帕里什-诺瓦克，J.等人（2000年）《自然》408卷，57 - 63页]。在本报告中，我们利用γc缺陷的X连锁重症联合免疫缺陷（XSCID）淋巴母细胞系JT以及用γc重建的JT细胞（JT/γc），证明γc也是IL-21受体（IL-21R）必需的信号传导成分。此外，我们证明在IL-21诱导的经基因工程改造表达人IL-21Rα的前B淋巴细胞（BaF3/IL-21Rα）增殖过程中，γc和与γc相关的Janus家族酪氨酸激酶3（JAK3）都有功能需求。逆转录病毒介导的野生型γc转导至XSCID JT细胞中可恢复IL-21R的功能，这在JT/γc细胞以及BaF3/IL-21Rα和原代脾B细胞中表现为IL-21诱导的JAK1和JAK3酪氨酸磷酸化以及下游信号转导子和转录激活子5（STAT5）的激活。相比之下，IL-21在未重建的JT细胞中无法激活JAK - STAT信号通路。针对γc链的单克隆抗体有效抑制了IL-21诱导的BaF3/IL-21Rα细胞生长，支持了该分子在IL-21R复合物中的功能作用。此外，特异性JAK3酪氨酸激酶抑制剂WHI - P131显著降低了IL-21诱导的BaF3/IL-21Rα细胞增殖。综上所述，这些结果明确证明IL-21介导的信号传导需要γc链，并表明JAK3是该细胞因子诱导的γc依赖性存活和/或促有丝分裂信号的重要转导分子。
