A new double-stranded RNA-binding protein that interacts with PKR
A new double-stranded RNA-binding protein that interacts with PKR
复制标题
DOI：
10.1093/nar/28.6.1407
复制
发表时间：
2000-03-15
影响因子：
14.9
通讯作者：
Patton, JG
中科院分区：
文献类型：
--
作者：
Coolidge, CJ;Patton, JG
我们已经确定了一个74 kDa的双链（ds）RNA结合蛋白，该蛋白与小鼠精子细胞核周RNA结合蛋白（Spnr）具有广泛的同源性。p74含有两个dsRNA结合基序（dsRBM），其对于优先结合dsRNA是必需的。此前，双链RNA结合蛋白被证明会发生同二聚化和异二聚化，这增加了活性调节可以通过不同家族成员之间的相互作用来控制的可能性。激活dsRNA依赖性蛋白激酶PKR需要同源二聚化，而PKR和其他dsRNA结合蛋白之间的异源二聚化可以抑制激酶活性。我们发现p74也与PKR相互作用，包括野生型酶和催化缺陷突变体（K296 R）。虽然p74和野生型PKR在酵母酿酒酵母中的共表达不改变PKR活性，但p74和催化缺陷型K296 R突变体的α-表达令人惊讶地导致保持高水平p74表达的转化体的异常形态和细胞死亡。这些转化体可以通过野生型真核生物翻译起始因子2（eIF 2 α）的α-亚基的过表达来拯救，所述α-亚基是PKR的已知底物之一。我们假设p74-K296 R PKR和eIF 2 α-K296 R PKR之间的竞争性异源二聚体可能控制细胞生长，使得p74-K296 R PKR异源二聚体的稳定诱导异常形态和细胞死亡。
We have identified a 74 kDa double-stranded (ds)RNA-binding protein that shares extensive homology with the mouse spermatid perinuclear RNA-binding (Spnr) protein. p74 contains two dsRNA-binding motifs (dsRBMs) that are essential for preferential binding to dsRNA. Previously, dsRNA-binding proteins were shown to undergo homo- and heterodimerization, raising the possibility that regulation of activity could be controlled by interactions between different family members. Homodimerization is required to activate the dsRNA-dependent protein kinase PKR, whereas heterodimerization between PKR and other dsRNA-binding proteins can inhibit kinase activity. We have found that p74 also interacts with PKR, both the wild-type enzyme and a catalytically defective mutant (K296R). While co-expression of p74 and wild-type PKR in the yeast Saccharomyces cerevisiae did not alter PKR activity, cc-expression of p74 and the catalytically defective K296R mutant surprisingly resulted in abnormal morphology and cell death in transformants that maintained a high level of p74 expression. These transformants could be rescued by overexpression of the a-subunit of wild-type eukaryotic translation initiation factor 2 (eIF2 alpha), one of the known substrates for PKR. We hypothesize that competing heterodimers between p74-K296R PKR and eIF2 alpha-K296R PKR may control cell growth such that stabilization of the p74-K296R PKR heterodimer induces abnormal morphology and cell death.