Date of Presentation
5-5-2022 12:00 AM
Embargo Period
11-5-2022
College
School of Osteopathic Medicine
Poster Abstract
Translation is tightly coupled to growth status. Efficient protein synthesis is necessary for cell growth in nutrient rich environments, while global translation inhibition combined with selective translation of stress-responsive mRNAs helps limit growth in times of stress. Environmental stress cues which inhibit the nutrient-sensing complex TORC1 are known to reduce general translation, but how does the cell alter protein synthesis machinery to adapt to these conditions? A few mechanisms to promote cell survival in nitrogen starvation include post-translational modification and selective degradation of specific mRNA-binding translation factors, as well as inhibition of activators of genes whose products are required for general translation. How and when these occur, however, have remained elusive. Here, we demonstrate in Saccharomyces cerevisiae that the highly conserved Cdk8 kinase module (CKM) of the mediator complex (cyclin C, Cdk8, Med13, and Med12) transcriptionally upregulates specific 60S ribosome proteins and translation initiation factors such as eIF4G1 to maintain steady state levels of translation-related proteins in physiological conditions. Yeast CKM is known to predominantly repress stress response genes (SRG), and our previous findings revealed that SRG suppression is relieved through the degradation of Med13 and cyclin C following both cell survival and death cues. Our recent data further suggest that degradation of the CKM following nitrogen starvation also plays a transcriptional role in fine-tuning the expression of translation-related proteins. The CKM is thus a multi-faceted hub that can provide insight to how the cell adapts to stress at the levels of transcription, translation, and degradation.
Keywords
Saccharomyces cerevisiae, Messenger RNA, Ribosomal Proteins, Cell Survival, Mediator Complex, Mechanistic Target of Rapamycin Complex 1, Cyclin C
Disciplines
Cell Biology | Laboratory and Basic Science Research | Medical Cell Biology | Medical Molecular Biology | Medicine and Health Sciences | Microbiology
Document Type
Poster
Included in
Cell Biology Commons, Laboratory and Basic Science Research Commons, Medical Cell Biology Commons, Medical Molecular Biology Commons, Microbiology Commons
Cdk8 Kinase Module Modifies Expression of Specific Translation-Related Proteins Before and After Stress
Translation is tightly coupled to growth status. Efficient protein synthesis is necessary for cell growth in nutrient rich environments, while global translation inhibition combined with selective translation of stress-responsive mRNAs helps limit growth in times of stress. Environmental stress cues which inhibit the nutrient-sensing complex TORC1 are known to reduce general translation, but how does the cell alter protein synthesis machinery to adapt to these conditions? A few mechanisms to promote cell survival in nitrogen starvation include post-translational modification and selective degradation of specific mRNA-binding translation factors, as well as inhibition of activators of genes whose products are required for general translation. How and when these occur, however, have remained elusive. Here, we demonstrate in Saccharomyces cerevisiae that the highly conserved Cdk8 kinase module (CKM) of the mediator complex (cyclin C, Cdk8, Med13, and Med12) transcriptionally upregulates specific 60S ribosome proteins and translation initiation factors such as eIF4G1 to maintain steady state levels of translation-related proteins in physiological conditions. Yeast CKM is known to predominantly repress stress response genes (SRG), and our previous findings revealed that SRG suppression is relieved through the degradation of Med13 and cyclin C following both cell survival and death cues. Our recent data further suggest that degradation of the CKM following nitrogen starvation also plays a transcriptional role in fine-tuning the expression of translation-related proteins. The CKM is thus a multi-faceted hub that can provide insight to how the cell adapts to stress at the levels of transcription, translation, and degradation.