Understanding the Regulation of Translational DEAD-box Helicases during Stress - ABSTRACT Adaptation to environmental stressors is essential for cellular survival, and regulation of translation plays a central role in this process by modulating protein levels and maintaining proteostasis. One key step in translation regulation is initiation, where messenger RNA (mRNA) is prepared for translation by recruiting ribosomal subunits. In eukaryotes DEAD-box helicases serve as translation initiation factors that activate mRNAs for translation and facilitate ribosomal scanning of the 5′ untranslated regions (UTRs) of transcripts. Despite their importance in maintaining proteostasis, the dynamic regulation of these helicases in response to stress remains poorly understood. We recently discovered a potential mechanism to regulate DEAD-box helicase activity during stress conditions when the mRNA cap-binding protein eIF4E is depleted. Disrupting this putative regulation reduces growth during eIF4E depletion, but paradoxically increase protein synthesis. Thus, I hypothesize that the loss of this DEAD-box helicase regulation disrupts translation and proteostasis during stress, leading to cytotoxic protein aggregation and reduced fitness. In Aim 1, I will test the proposed regulation of DEAD-box helicase activity by measuring changes in helicase function in vitro. In Aim 2, I will examine the translational and proteostatic effects of ablating DEAD-box helicase regulation during translational stress caused by eIF4E depletion. In Aim 3, I will identify additional environmental stressors where DEAD-box helicase regulation is critical, expanding our understanding of how translational control adapts to cellular perturbations. This project will provide new insights into the mechanisms of translational regulation during stress and highlight how cells dynamically adjust protein synthesis to maintain proteostasis in changing environments.
