Arc1p is a yeast-specific tRNA-binding protein that forms a ternary complex with glutamyl-tRNA synthetase (GluRSc) and methionyl-tRNA synthetase (MetRS) in the cytoplasm to regulate their catalytic activities and subcellular distributions. Despite Arc1p not being involved in any known biotin-dependent reaction, it is a natural target of biotin modification. Results presented herein show that biotin modification had no obvious effect on Arc1p's growth-supporting activity, subcellular distribution, tRNA binding, or interactions with GluRSc and MetRS. Nevertheless, biotinylation of Arc1p was temperature dependent; raising the growth temperature from 30oC to 37oC drastically reduced its biotinylation level. As a result, Arc1p purified from a yeast culture that had been grown overnight at 37oC was essentially biotin free. Non-biotinylated Arc1p was more heat stable, more flexible in structure, and more effective than its biotinylated counterpart in promoting glutamylation activity of the otherwise inactive GluRSc at 37oC in vitro. Our study suggests that the structure and function of Arc1p can be modulated via biotinylation in response to temperature changes.
Date:
2016-08
Relation:
Journal of Biological Chemistry. 2016 Aug 21;291(33):17102-17111.
