Uncharged tRNA activates GCN2 by displacing the protein kinase moiety from a bipartite tRNA-Binding domain

被引：380

作者：

Dong, JS ^{[1
]}

Qiu, HF ^{[1
]}

Garcia-Barrio, M ^{[1
]}

Anderson, J ^{[1
]}

Hinnebusch, AG ^{[1
]}

机构：

[1] NICHHD, Lab Eukaryot Gene Regulat, Bethesda, MD 20892 USA

来源：

MOLECULAR CELL | 2000年 / 6卷 / 02期

关键词：

D O I：

10.1016/S1097-2765(00)00028-9

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Protein kinase GCN2 regulates translation in amino acid-starved cells by phosphorylating eIF2. GCN2 contains a regulatory domain related to histidyl-tRNA synthetase (HisRS) postulated to bind multiple deacylated tRNAs as a general sensor of starvation. In accordance with this model, GCN2 bound several deacylated tRNAs with similar affinities, and aminoacylation of tRNA(Phe) weakened its interaction with GCN2. Unexpectedly, the C-terminal ribosome binding segment of GCN2 (C-term) was required in addition to the HisRS domain for strong tRNA binding. A combined HisRS+ C-term segment bound to the isolated protein kinase (PK) domain in vitro, and tRNA impeded this interaction. An activating mutation (GCN2(C)-E803V) that weakens PK-C-term association greatly enhanced tRNA binding by GCN2. These results provide strong evidence that tRNA stimulates the GCN2 kinase moiety by preventing an inhibitory interaction with the bipartite tRNA binding domain.

引用

页码：269 / 279

页数：11