Cloning and characterization of a mouse IL-12 receptor-beta component.
Cloning and characterization of a mouse IL-12 receptor-beta component.
复制标题
小鼠 IL-12 受体-β 成分的克隆和表征。
DOI：
10.4049/jimmunol.155.9.4286
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发表时间：
1995
影响因子：
4.4
通讯作者：
U. Gubler
中科院分区：
文献类型：
--
作者：
A. O. Chua;V. Wilkinson;D. Presky;U. Gubler
使用DNA交叉杂交，我们已经分离和表征cDNA克隆编码小鼠（MO）IL-12 R β组分。发现了两种形式的cDNA，第一种形式编码的受体蛋白具有与已知的人（hu）IL-12 R β非常相似的总体结构，具有54%的氨基酸同一性，而在第二种类型的小鼠cDNA中，跨膜区的等同物已被删除。这种假定的选择性剪接事件也引起移码，导致具有相同胞外结构域但不同C-末端序列的受体。这个替代的C末端是否能够发出信号尚不清楚。当在COS-7细胞中表达时，两种类型的受体都是膜结合的，并且以1 nM的亲和力结合moIL-12，类似于huIL-12 R β对huIL-12的亲和力。两种moIL-12 R β蛋白的单体大小均为约100 kDa。与huIL-12 R β类似，moIL-12 R β在COS-7和Ba/F3细胞表面表达为二聚体/寡聚体，其形成不依赖于IL-12结合。当在Ba/F3细胞中表达时，moIL-12 R β以50和470 pM的两种亲和力结合moIL-12，对应于先前在小鼠Con A淋巴母细胞上鉴定的中等和高亲和力IL-12结合位点。尽管Ba/F3细胞中moIL-12 R β显示出更高的亲和力，但这种受体本身不足以抑制信号，这表明可能需要另一个亚基来产生功能性moIL-12 R复合物。
Using DNA cross-hybridization, we have isolated and characterized cDNA clones encoding a mouse (mo) IL-12R beta component. Two forms of cDNA were found. The first form encodes a receptor protein that has an overall structure very similar to that of the known human (hu) IL-12R beta with 54% amino acid identity, whereas in the second type of mouse cDNA, the equivalent of the transmembrane region has been deleted. This presumed alternative splicing event also gives rise to a frame shift that results in a receptor with an identical extracellular domain but a different C-terminal sequence. Whether this alternative C terminus is capable of signaling is not yet known. Both types of receptors when expressed in COS-7 cells are membrane associated and bind moIL-12 with an affinity of 1 nM, similar to the affinity of huIL-12R beta for huIL-12. The monomeric size of both moIL-12R beta proteins is about 100 kDa. Similar to huIL-12R beta, moIL-12R beta is expressed at the surface of COS-7 and Ba/F3 cells as a dimer/oligomer whose formation is independent of IL-12 binding. When expressed in Ba/F3 cells, moIL-12R beta binds moIL-12 with two affinities of 50 and 470 pM, corresponding to the medium and high affinity IL-12 binding sites previously identified on mouse Con A lymphoblasts. Despite the higher affinity displayed by the moIL-12R beta in Ba/F3 cells, this receptor alone is not sufficient to transduce a signal, suggesting that another subunit is probably required to generate a functional moIL-12R complex.