Sugamura K, Takeshita T, Asao H, Kumaki S, Ohbo K, Ohtani K, Nakamura M
Department of Microbiology, Tohoku University School of Medicine, Sendai, Japan.
Tohoku J Exp Med. 1992 Oct;168(2):231-7. doi: 10.1620/tjem.168.231.
We previously demonstrated the existence of a third component, p64, of IL-2 receptor (IL-2R), tentatively named the gamma chain of IL-2R. Our recent studies provided evidence suggesting that the gamma chain endows the beta chain of IL-2R with IL-2 binding ability. The gamma chain was detected in lymphoid transfectants of IL-2R beta cDNA, which showed the intermediate-affinity IL-2R, but not in nonlymphoid transfectants of IL-2R beta cDNA, which showed no IL-2 binding activity. The comparative study between two subclones of lymphoid MOLT4 transfectant of IL-2R beta cDNA demonstrated that the amount of the gamma chain coprecipitated with IL-2R beta was proportional to numbers of the IL-2 binding sites. These results suggest the possibility that the gamma chain associates with IL-2R beta and has an important role in formation of the intermediate-affinity IL-2R complex. On the other hand, we have also demonstrated the association of IL-2R beta with a certain tyrosine kinase, of which activation by IL-2 could be indispensable process at the initial pathway of signal transduction.
我们先前证明了白细胞介素-2受体（IL-2R）存在第三种成分p64，暂命名为IL-2R的γ链。我们最近的研究提供了证据，表明γ链赋予IL-2R的β链IL-2结合能力。在显示中等亲和力IL-2R的IL-2RβcDNA的淋巴样转染子中检测到γ链，但在不显示IL-2结合活性的IL-2RβcDNA的非淋巴样转染子中未检测到。对IL-2RβcDNA的淋巴样MOLT4转染子的两个亚克隆进行的比较研究表明，与IL-2Rβ共沉淀的γ链量与IL-2结合位点的数量成正比。这些结果提示γ链与IL-2Rβ相关联并在中等亲和力IL-2R复合物形成中起重要作用的可能性。另一方面，我们还证明了IL-2Rβ与某种酪氨酸激酶相关联，其中IL-2对其激活可能是信号转导初始途径中不可或缺的过程。
