Decoding the impact of disease-causing mutations in an essential aminoacyl-tRNA synthetase.

Aminoacyl-tRNA synthetases (aaRSs) are housekeeping enzymes that catalyze the specific attachment of amino acids onto cognate tRNAs, providing building blocks for ribosomal protein synthesis. Due to the absolutely essential nature of these enzymes, the possibility that mutations in their sequence could be the underlying cause of diseases had not been foreseen. However, we are learning of patients bearing familial mutations in aaRSs at an exponential rate. In a recent issue of JBC, Jin and coworkers analyzed the impact of two such mutations in the very special bi-functional human glutamyl-prolyl-tRNA synthetase (EPRS) and convincingly decode how these mutations elicit the integrated stress response.