Protein with different functions depending on its subcellular location: involved in miRNA processing in the nucleus and acts as a tRNA pseudouridylate synthase in the cytoplasm. In the cytoplasm, acts as a pseudouridylate synthase by catalyzing synthesis of pseudouridine(54) and pseudouridine(55) from uracil-54 and uracil-55, respectively, in the psi GC loop of a subset of tRNAs. tRNA pseudouridylate synthase activity is enhanced by the presence of 1-methyladenosine at position 53-61 of tRNAs. Does not show tRNA pseudouridylate synthase activity in the nucleus. In the nucleus, promotes primary microRNAs (pri-miRNAs) processing independently of its RNA pseudouridylate synthase activity. Binds pri-miRNAs. uridine(55) in tRNA = pseudouridine(55) in tRNA uridine(54) in tRNA = pseudouridine(54) in tRNA Localizes mainly in the nucleus. tRNA pseudouridylate synthase activity is restricted to the cytoplasm. Belongs to the pseudouridine synthase Pus10 family.