Sadir R, Lambert A, Lortat-Jacob H, Morel G
CNRS UMR 5578, Université Claude Bernard-Lyon 1, Villeurbanne, France.
Cytokine. 2001 Apr 7;14(1):19-26. doi: 10.1006/cyto.2000.0854.
Interferon-gamma (IFN-gamma) elicits a variety of activities following binding to its cell-surface-specific receptor (IFN-gammaR). This complex formation leads to the activation of the Jak-STAT pathway. Several hypotheses have been proposed to explain the role and location of the receptor and its ligand in the signalling pathway. In vivo as well as in vitro, the present study shows that IFN-gamma and its receptor were internalized in different cellular compartments including cytoplasmic matrix, mitochondria and nucleus. In order to analyse the internalization pathway of IFN-gamma and its receptor, we have study in vivo and in vitro their colocalization with clathrin and caveolin by using double immunogold-labelling experiments using electron microscopy. We demonstrate that IFN-gamma and IFN-gammaR were colocalized in the caveolin-containing structures and the clathrin-coated pits suggesting that both internalization pathways may be used. This indicates that IFN-gamma and IFN-gammaR were internalized by these two different pathways, suggesting two different intracellular routes probably for different target cell-compartments.
γ干扰素（IFN-γ）与其细胞表面特异性受体（IFN-γR）结合后会引发多种活性。这种复合物的形成会导致Jak-STAT信号通路的激活。已经提出了几种假说来解释受体及其配体在信号通路中的作用和位置。本研究表明，在体内以及体外，IFN-γ及其受体被内化到包括细胞质基质、线粒体和细胞核在内的不同细胞区室中。为了分析IFN-γ及其受体的内化途径，我们通过电子显微镜使用双重免疫金标记实验在体内和体外研究了它们与网格蛋白和小窝蛋白的共定位。我们证明IFN-γ和IFN-γR在含有小窝蛋白的结构和网格蛋白包被的小窝中共定位，这表明两种内化途径都可能被使用。这表明IFN-γ和IFN-γR通过这两种不同的途径被内化，这可能意味着针对不同靶细胞区室存在两条不同的细胞内途径。
