QTGAL (queuosine-tRNA galactosyltransferase) is a glycosyltransferase that catalyzes the galactosylation of cytoplasmic tRNA(Tyr) modified with queuosine at position 34 (Q34), specifically transferring galactose to the cyclopentene hydroxyl group to form galactosyl-queuosine(34) 1. This modification is a post-transcriptional tRNA process that regulates protein translation with high specificity 2. Mechanistically, QTGAL-mediated galactosylation slows ribosomal elongation at cognate UAC codons and suppresses stop codon readthrough, thereby optimizing translational kinetics 1. The modification also enhances proteostasis, as cells lacking Q-glycosylation accumulate protein aggregates 1. Cryo-EM structural analysis has revealed the molecular basis of codon recognition regulated by Q-glycosylations 1. Developmentally, QTGAL is essential for post-embryonic growth; zebrafish qtgal knockout lines display shortened body length, indicating physiological significance in vertebrate development 1. Given its roles in translation regulation and proteostasis, QTGAL dysregulation has been associated with various human diseases including cancer and inflammatory and neurological disorders 3.