Diallinas G, Thireos G
Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece.
Gene. 1994 May 27;143(1):21-7. doi: 10.1016/0378-1119(94)90599-1.
The GCN2 (general control kinase 2) protein is an eIF2-alpha (eukaryotic initiation factor alpha) kinase which mediates translational derepression of the yeast general control transcriptional activator, GCN4, upon amino-acid starvation. We isolated and characterized GCN2 mutations differentially affecting GCN2 function. Mutations mapping in, or close to, the ATP-binding site of the kinase moiety result in constitutively activated GCN2 molecules. A C-terminal regulatory mutation dramatically affects translation initiation rates resulting in pleiotropic phenotypes. The effect of mutations in both regions were found to depend on eIF2-alpha phosphorylation. We have demonstrated that GCN2 mutants have altered autophosphorylation activities in vitro, depending on the presence or absence of a wild-type GCN2 gene and that GCN2 elutes in gel-filtration chromatography fractions with high apparent molecular mass. Both these genetic and biochemical findings suggest that GCN2 functioning might involve polymerization to form dimers or tetramers.
GCN2（通用控制激酶2）蛋白是一种真核起始因子α（eIF2-α）激酶，在氨基酸饥饿时介导酵母通用控制转录激活因子GCN4的翻译去抑制。我们分离并鉴定了对GCN2功能有不同影响的GCN2突变。位于激酶部分ATP结合位点内或附近的突变导致GCN2分子组成型激活。一个C末端调节突变显著影响翻译起始速率，导致多效性表型。发现这两个区域的突变效应均依赖于eIF2-α磷酸化。我们已经证明，GCN2突变体在体外具有改变的自磷酸化活性，这取决于野生型GCN2基因的存在与否，并且GCN2在凝胶过滤色谱级分中以高表观分子量洗脱。这些遗传和生化发现均表明，GCN2的功能可能涉及聚合形成二聚体或四聚体。
