Wek R C
Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202-5122.
Trends Biochem Sci. 1994 Nov;19(11):491-6. doi: 10.1016/0968-0004(94)90136-8.
Phosphorylation of eukaryotic initiation factor-2 (eIF-2) is an important mechanism regulating general translation initiation. Two mammalian eIF-2 kinases, the double-stranded-RNA-dependent kinase (PKR) and heme-regulated inhibitor kinase (HRI), have been characterized by sequencing, revealing shared sequence and structural features distinct from other eukaryotic protein kinases. Recent work in yeast has shown that a third related kinase, GCN2, also phosphorylates the regulated site in eIF-2. However, unlike the mammalian kinases, this kinase regulates gene-specific translation. Current models are presented for the regulation of each eIF-2 kinase, and the molecular basis for how this general form of regulation is adapted to control expression of a single species of messenger RNA is discussed.
真核生物起始因子2（eIF-2）的磷酸化是调节一般翻译起始的重要机制。两种哺乳动物eIF-2激酶，即双链RNA依赖性激酶（PKR）和血红素调节抑制激酶（HRI），已通过测序得以鉴定，揭示出与其他真核蛋白激酶不同的共有序列和结构特征。酵母中的最新研究表明，第三种相关激酶GCN2也可使eIF-2中的调节位点磷酸化。然而，与哺乳动物激酶不同的是，这种激酶调节基因特异性翻译。本文提出了每种eIF-2激酶的调节模型，并讨论了这种一般调节形式如何适应控制单一信使RNA物种表达的分子基础。
