Biology subjects

Katanski, C. D.

Publications and source records attributed to Katanski, C. D..

2 recordsLinked to original sources

bioRxiv2023

Modifications in the T arm of tRNA globally determine tRNA maturation, function and cellular fitness

All elongator tRNAs harbor 5-methyluridine 54 and pseudouridine 55 in the T arm, which are generated by the enzymes TrmA and TruB, respectively. Escherichia coli TrmA and TruB both act as tRNA chaperones, and strains lacking trmA or truB are outcompeted by wildtype. Here, we investigate how TrmA and TruB contribute to cellular fitness. Deletion of trmA and truB in E. coli causes a global decrease in aminoacylation and alters other tRNA modification such as acp3U47. Whereas overall protein synthesis is not affected in {Delta}trmA and {Delta}truB strains, the translation of a specific subset of codons is significantly impaired, and the expression of many specific proteins is translationally changed. In conclusion, we demonstrate that universal modifications of the tRNA T arm are critical for global tRNA function by enhancing tRNA maturation, tRNA aminoacylation, and translation, thereby improving cellular fitness and explaining trmA and truB conservation.

molecular biology↗

bioRxiv2018

Transient intracellular acidification regulates the core transcriptional heat shock response

Heat shock induces a conserved transcriptional program regulated by heat shock factor 1 (Hsf1) in eukaryotic cells. Activation of this heat-shock response is triggered by heat-induced misfolding of newly synthesized polypeptides, and so has been thought to depend on ongoing protein synthesis. Here, using the the budding yeast Saccharomyces cerevisiae, we report the discovery that Hsf1 can be robustly activated when protein synthesis is inhibited, so long as cells undergo cytosolic acidification. Heat shock has long been known to cause transient intracellular acidification which, for reasons which have remained unclear, is associated with increased stress resistance in eukaryotes. We demonstrate that acidification is required for heat shock response induction in translationally inhibited cells, and specifically affects Hsf1 activation. Physiological heat-triggered acidification also increases population fitness and promotes cell cycle reentry following heat shock. Our results uncover a previously unknown adaptive dimension of the well-studied eukaryotic heat shock response.

cell biology↗