NOVEL INTERLEUKIN-2 RECEPTOR SUBUNIT DETECTED BY CROSS-LINKING UNDER HIGH-AFFINITY CONDITIONS
NOVEL INTERLEUKIN-2 RECEPTOR SUBUNIT DETECTED BY CROSS-LINKING UNDER HIGH-AFFINITY CONDITIONS
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DOI：
10.1126/science.3095922
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发表时间：
1986-11-14
期刊：
影响因子：
56.9
通讯作者：
LEONARD, WJ
中科院分区：
文献类型：
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作者：
SHARON, M;KLAUSNER, RD;LEONARD, WJ
白细胞介素-2（IL-2）与活化T淋巴细胞上的高亲和力和低亲和力IL-2受体结合。只有高亲和力受体参与受体介导的内吞作用，并通常抑制IL-2的促有丝分裂信号;然而，区分高亲和力和低亲和力受体的结构特征尚不清楚。当125 I标记的IL-2与活化的人T淋巴细胞化学交联时，鉴定出两个主要条带。首先，如预测的那样，观察到由与IL-2受体（55千道尔顿）交联的IL-2（15.5千道尔顿）组成的68- 72千道尔顿条带。其次，检测到一个不可预测的85至92千道尔顿部分。当IL-2与转染的C127细胞交联时，该条带不存在，所述转染的C127细胞仅表达低亲和力受体。所提供的数据与70- 77千道尔顿糖蛋白亚基（p70）的存在最为一致，该亚基在与55千道尔顿低亲和力受体（p55）结合后，将其转化为高亲和力位点。建议将p55和p70称为α。和β亚基，分别为高亲和力IL-2受体。
Interleukin-2 (IL-2) binds to both high- and low-affinity classes of IL-2 receptors on activated T lymphocytes. Only the high-affinity receptors are involved in receptor-mediated endocytosis and normally transduce the mitogenic signals of IL-2; however, the structural features distinguishing the high- and low-affinity receptors are unknown. When 125I-labeled IL-2 was chemically cross-linked to activated human T lymphocytes, two major bands were identified. First, as predicted, a 68- to 72-kilodalton band, consisting of IL-2 (15.5 kilodaltons) cross-linked to the IL-2 receptor (55 kilodaltons), was observed. Second, an unpredicted 85- to 92-kilodalton moiety was detected. This band was not present when IL-2 was cross-linked to transfected C127 cells, which exclusively express low-affinity receptors. The data presented are most consistent with the existence of a 70- to 77-kilodalton glycoprotein subunit (p70) which, upon associating with the 55-kilodalton low-affinity receptor (p55), transforms it into a high-affinity site. It is proposed that p55 and p70 be referred to as the .alpha. and .beta. subunits, respectively, of the high-affinity IL-2 receptor.