Investigating the Role of Ola1 in Translational Control

Abstract

Protein synthesis is a central activity of all cells, it requires a high level of control and regulation. The initiation phase of translation requires at least twelve initiation factors and an initiator transfer RNA (Met-tRNAi) in addition to the 40S and 60S ribosomal subunits to assemble the 80S ribosome that synthesises proteins. Initiation begins with the formation of the eIF2:GTP:Met-tRNAi ternary complex, which facilitates the recruitment of Met-tRNAi to the 40S subunit continuing with the initiation phase. Several studies were dedicated to understanding the mechanism behind the eIF2-ternary complex formation and the activation of eIF2. Recently, mammalian Obg-like ATPase1 (Ola1) was described as a novel eIF2-regulator in response to stress. As a GTPase, Ola1 was proposed to directly bind to eIF2 and hydrolyse GTP, preventing the generation of the eIF2-ternary complex, and as a consequence, inhibiting global protein synthesis. Since it was first characterised in 2007, Ola1, a member of the highly conserved Obg family of P-loop GTPases, has been implicated in a diverse range of cellular processes although the physiological role of this protein is not yet understood. This project aimed to uncover the role of Ola1 in translational regulation during stress that induced the integrated stress response (ISR), namely oxidative stress and amino acid starvation, using Saccharomyces cerevisiae as a model organism. A combination of molecular biology, yeast genetics, biochemistry, and proteomics approaches revealed a potential regulatory role of Ola1 in translation elongation or termination as it alters the Gcn2-mediated ISR response to stress and affects global translation. In addition, proteomics data uncovered some potential roles of Ola1 and the 40S ribosomal protein Asc1 in cellular stress response and maintaining cellular functions and homeostasis.

Date of Award	1 Aug 2023
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Graham Pavitt (Supervisor) & Raymond O'Keefe (Supervisor)