The function of YRDC (yrdC N6-threonylcarbamoyltransferase domain containing, ENSG00000196449) is as follows. Cytoplasmic and mitochondrial threonylcarbamoyl-AMP synthase required for the formation of a threonylcarbamoyl group on adenosine at position 37 (t(6)A37) in tRNAs that read codons beginning with adenine (PubMed:29760464, PubMed:31481669, PubMed:34545459). Catalyzes the conversion of L-threonine, HCO(3)(-)/CO(2) and ATP to give threonylcarbamoyl-AMP (TC-AMP) as the acyladenylate intermediate, with the release of diphosphate (PubMed:29760464). Participates in t(6)A37 formation in cytoplasmic and mitochondrial tRNAs (PubMed:29760464). May regulate the activity of some transporters (By similarity). {ECO:0000250|UniProtKB:Q3U5F4, ECO:0000269|PubMed:29760464, ECO:0000269|PubMed:31481669, ECO:0000269|PubMed:34545459}.