Structure of a Gcn2 dimer in complex with the large 60S ribosomal subunit

• 成果类型: Article
• 署名作者: Paternoga, Helge; Xia, Lu; Paternoga, Lyudmila Dimitrova -; Li, Sihan; Yan, Liewei L.; Oestereich, Malte; Kasvandik, Sergo; Urs, Ankanahalli N. Nanjaraj; Beckert, Bertrand; Tenson, Tanel; Zaher, Hani; Inada, Toshifumi; Wilson, Daniel N.
• 署名单位: University of Hamburg; University of Tokyo; Washington University (WUSTL); University of Tartu; Swiss Federal Institutes of Technology Domain; Ecole Polytechnique Federale de Lausanne
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-14554
• DOI: 10.1073/pnas.2415807122
• 发表日期: 2025-04-15
• 关键词: transfer-rna synthetase; protein-kinase gcn2; amino-acid control; quality-control; crystal-structures; rwd domain; gi domain; activation; binding; yeast

摘要

The integrated stress response (ISR) is a central signaling network that enables eukaryotic cells to respond to a variety of different environmental stresses. Such stresses cause ribosome collisions that lead to activation of the kinase Gcn2, resulting in the phosphorylation and inactivation of eukaryotic initiation factor 2 and thereby promoting selective translation of mRNAs to restore homeostasis. Despite the importance of the ISR and intensive study over the past decades, structural insight into how Gcn2 interacts with ribosomal particles has been lacking. Using ex vivo affinity purification approaches, we have obtained a cryoelectron microscopy structure of a yeast Gcn2 dimer in complex with the ribosomal 60S subunit. The Gcn2 dimer is formed by dimerization of the histidine tRNA synthetase- like domains, which establish extensive interactions with the stalk- base and sarcin-ricin loop of the 60S subunit. The C- terminal domain of Gcn2 is also dimerized and occupies the A- and P- site tRNA binding sites at the peptidyl- transferase center the 60S subunit into the colliding ribosome fraction, suggesting that the Gcn2-60S complex represents an inactive stand- by state to enable a rapid redistribution to collided ribosomes, and thereby facilitating a quick and efficient response to stress.