ROLE OF INTERFERON-ALPHA/BETA RECEPTOR CHAIN-1 IN THE STRUCTURE AND TRANSMEMBRANE SIGNALING OF THE INTERFERON-ALPHA/BETA RECEPTOR COMPLEX
ROLE OF INTERFERON-ALPHA/BETA RECEPTOR CHAIN-1 IN THE STRUCTURE AND TRANSMEMBRANE SIGNALING OF THE INTERFERON-ALPHA/BETA RECEPTOR COMPLEX
复制标题
DOI：
10.1073/pnas.91.20.9602
复制
发表时间：
1994-09-27
影响因子：
11.1
通讯作者：
PFEFFER, LM
中科院分区：
文献类型：
--
作者：
CONSTANTINESCU, SN;CROZE, E;PFEFFER, LM
先前克隆的cDNA编码人干扰素α/β受体（IFN α R）的一个亚基，表示为IFN α R1。为了研究IFN α R1的表达和信号传导，我们使用针对杆状病毒表达的IFN α R1胞外域产生的单克隆抗体（mAb）。免疫沉淀和免疫印迹的裂解物从各种人类细胞系表明，IFN α R1具有135 kDa的表观分子量。用I-125标记的mAb进行的结合分析表明，在人细胞和用IFN α R1 cDNA转染的小鼠细胞中，IFN α R1的细胞表面表达水平较高，而在仅表达内源性小鼠受体的对照小鼠L929细胞中未观察到交叉反应性。该亚基被IFN α迅速下调（2小时内下降80%），并在内化后降解。IFN α R1链似乎与IFN α/β受体的115-kDa亚基组成型相关，因为mAb共沉淀该蛋白质。IFN α/β治疗诱导1分钟内IFN α R1的酪氨酸磷酸化，与IFN活化蛋白酪氨酸激酶Jak 1和Tyk 2的动力学平行。配体诱导的IFN α R1酪氨酸磷酸化被激酶抑制剂染料木黄酮或星形孢菌素阻断。虽然IFN α R1 cDNA转染的小鼠细胞表达高水平的这种亚基时，与空载体转染的细胞相比，结合位点的人IFN α（50-75个网站每个细胞）的数量没有增加。在用IFN α R1 cDNA转染的小鼠L929细胞中，人IFN α诱导小鼠IFN α/β应答基因（204基因）的表达，但在模拟转染细胞中不诱导。这些结果表明，IFN α R1亚基作为IFN α/β受体复合物的物种特异性信号转导成分。
A previously cloned cDNA encodes one subunit of the human interferon alpha/beta receptor (IFN alpha R), denoted IFN alpha R1. To study the expression and signaling of IFN alpha R1, we used monoclonal antibodies (mAbs) generated against the baculovirus-expressed ectodomain of IFN alpha R1. Immunoprecipitation and immunoblotting of lysates from a variety of human cell lines showed that IFN alpha R1 has an apparent molecular mass of 135 kDa. Binding analysis with I-125-labeled mAb demonstrated high levels of cell surface expression of IFN alpha R1 in human cells and in mouse cells transfected with IFN alpha R1 cDNA, whereas no cross-reactivity was observed in control mouse L929 cells expressing only the endogenous mouse receptor. The subunit was rapidly down-regulated by IFN alpha (80% decrease within 2 hr) and degraded upon internalization. The IFN alpha R1 chain appeared to be constitutively associated with the 115-kDa subunit of the IFN alpha/beta receptor, since the mAbs coprecipitated this protein. IFN alpha/beta treatment induced tyrosine phosphorylation of IFN alpha R1 within 1 min, with kinetics paralleling that of the IFN-activated protein-tyrosine kinases Jak1 and Tyk2. Ligand-induced tyrosine phosphorylation of IFN alpha R1 was blocked by the kinase inhibitors genistein or staurosporine. Although IFN alpha R1 cDNA-transfected mouse cells expressed high levels of this subunit when compared with empty vector-transfected cells, the number of binding sites for human IFN alpha (50-75 sites per cell) was not increased. Human IFN alpha induced the expression of a mouse IFN alpha/beta-responsive gene (the 204 gene) in mouse L929 cells transfected with the IFN alpha R1 cDNA, but not in mock-transfected cells. These results suggest that the IFN alpha R1 subunit acts as a species-specific signal transduction component of the IFN alpha/beta receptor complex.