Poster abstracts

Poster number 69 submitted by Amanda Kyle

Phenylalanyl-tRNA synthetase regulated quality control is linked to stress responses in Saccharomyces cerevisiae

Amanda Kyle (Department of Microbiology, The Ohio State University), Rebecca Mann (Department of Microbiology, The Ohio State University), Kyle Mohler (Department of Microbiology, The Ohio State University), Michael Ibba (Department of Microbiology, The Ohio State University)

Abstract:
Compared to other essential cellular processes, translation is more error-prone, with an error rate of approximately 1 in 104 codons1. In translation, aminoacyl-tRNA synthetases (aaRSs) are enzymes which bind amino acids to cognate tRNAs1. AaRSs have editing processes to prevent the misincorporation of structurally similar amino acids into proteins1. Recently, it has been shown that phenylalanyl-tRNA synthetase (PheRS) quality control is important in the regulation of the general amino acid control (GAAC) pathway in Saccharomyces cerevisiae2. To further explore how quality control affects S. cerevisiae, the growth of a PheRS editing deficient strain was compared to a wild-type (WT) strain in many conditions using phenotypic microarrays. Conditions where differences in growth were observed were assigned to genes with previously established relationships to those chemicals. Many of these genes were associated with the target of rapamycin (TOR) and GAAC pathways3. When grown in caffeine supplemented media, the PheRS editing deficient strain was more tolerant to caffeine than the WT strain3. There is evidence linking mutations in the TOR pathway to differential growth in caffeine3. To explore the relationship between PheRS quality control and the TOR pathway, growth of ∆TOR WT and ∆TOR PheRS editing deficient strains were compared in a chronological lifespan assay. It has been previously documented that ∆TOR yeast mutants have prolonged chronological lifespans3. However, we observed that the ∆TOR mutation in the PheRS editing deficient strain had a decreased effect on chronological lifespan compared to the ∆TOR WT strain. This evidence suggests a relationship between PheRS regulated quality control and stress responses in S. cerevisiae. Since translation is a comparatively error-prone cellular process and there is evidence that mistranslation may be advantageous1, it is important to understand how lacking quality control affects the cell.

References:
1. Reynolds, N.M., Lazazzera, B.A., and Ibba, M. Cellular mechanisms that control mistranslation. Nature Reviews Microbiology. 2010, 8, 849-856.
2. Mohler, K., Mann, R., Bullwinkle, T.J., Hopkins, K., Hwang, L., Reynolds, N.M., Gassaway, B., Hans-Rudolf, A., Rinehart, J., Polymenis, M., Faull, K. and Ibba, M. Editing of misaminoacylated tRNA controls the sensitivity of amino acid stress responses in Saccharomyces cerevisiae. Nucleic Acids Research. 2017, 45, 3985-3996.
3. Mohler, K., Mann, R., Kyle, A., Reynolds, N. and Ibba, M. Aminoacyl-tRNA Quality Control is Required for Efficient Activation of the TOR Pathway Regulator Gln3p. RNA Biology, In press.

Keywords: aminoacyl-tRNA, TOR pathway, Saccharomyces cerevisiae