Uncharged tRNA Activates GCN2 by Displacing the Protein Kinase Moiety from a Bipartite tRNA-Binding Domain

Authors

Jinsheng Dong, National Institute of Child Health and Human Development
Hongfang Qiu, National Institute of Child Health and Human Development
Minerva Garcia-Barrio, National Institute of Child Health and Human Development
James T. Anderson, Marquette UniversityFollow
Alan G. Hinnebusch, National Institute of Child Health and Human DevelopmentFollow

Document Type

Article

Language

eng

Format of Original

11 p.

Publication Date

8-2000

Publisher

Elsevier (Cell Press)

Source Publication

Molecular Cell

Source ISSN

1097-2765

Original Item ID

doi: 10.1016/S1097-2765(00)00028-9

Abstract

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.

Comments

Accepted version. Molecular Cell, Vol. 6, No. 2 (August 2000): 269-279. DOI. © 2000 Cell Press. Used with permission.

Recommended Citation

Dong, Jinsheng; Qiu, Hongfang; Garcia-Barrio, Minerva; Anderson, James T.; and Hinnebusch, Alan G., "Uncharged tRNA Activates GCN2 by Displacing the Protein Kinase Moiety from a Bipartite tRNA-Binding Domain" (2000). Biological Sciences Faculty Research and Publications. 498.
https://epublications.marquette.edu/bio_fac/498