S-adenosyl-L-methionine-dependent methyltransferase that catalyzes the formation of 5-methyl-uridine in tRNAs and some mRNAs ( ). Mainly catalyzes the methylation of uridine at position 54 (m5U54) in cytosolic tRNAs (, ). Also able to mediate the formation of 5-methyl-uridine in some mRNAs .
Subcellular locations: Cytoplasm, Cytosol