Clemens M J
Department of Cellular and Molecular Sciences, St George's Hospital, Medical School, London, U.K.
Int J Biochem Cell Biol. 1997 Jul;29(7):945-9. doi: 10.1016/s1357-2725(96)00169-0.
The RNA-regulated protein kinase, (PKR) is an interferon-inducible enzyme of widespread occurrence in eukaryotic organisms. This serine/threonine-specific protein kinase is activated by double-stranded RNA by a mechanism involving autophosphorylation. Once activated, the enzyme phosphorylates the alpha subunit of protein synthesis initiation factor eIF2, thereby inhibiting translation. Recent evidence suggests that there may be additional substrates, and that signal transduction and gene transcription pathways also may be regulated by the protein kinase. As well as being important in mediating the antiviral effects of interferons, PKR is implicated in regulating cell proliferation in uninfected cells and may have a tumour suppressor function under normal conditions. Studies using cell lines expressing inactive mutants of PKR and mice with homozygous disruptions of the PKR gene are leading to greater insights into the biological significance of this enzyme.
RNA 调节蛋白激酶（PKR）是一种在真核生物中广泛存在的干扰素诱导酶。这种丝氨酸/苏氨酸特异性蛋白激酶通过一种涉及自身磷酸化的机制被双链 RNA 激活。一旦被激活，该酶就会使蛋白质合成起始因子 eIF2 的α亚基磷酸化，从而抑制翻译。最近的证据表明，可能存在其他底物，并且信号转导和基因转录途径也可能受到该蛋白激酶的调节。除了在介导干扰素的抗病毒作用中起重要作用外，PKR 还参与调节未感染细胞中的细胞增殖，并且在正常情况下可能具有肿瘤抑制功能。使用表达 PKR 无活性突变体的细胞系和 PKR 基因纯合缺失的小鼠进行的研究，正在使人们对这种酶的生物学意义有更深入的了解。
