FunctionRNA methyltransferase that methylates tRNAs, and possibly RNA polymerase III transcripts. Methylates cytosine to 5-methylcytosine (m5C) at position 34 of intron-containing tRNA(Leu)(CAA) precursors. Not able to modify tRNAs at positions 48 or 49. May act downstream of Myc to regulate epidermal cell growth and proliferation.
Sequence similaritiesBelongs to the methyltransferase superfamily. RsmB/NOP family. TRM4 subfamily.
Post-translational modificationsPhosphorylated at Ser-139 by Aurora-B/STK12 during mitosis, leading to abolish methyltransferase activity and the interaction with NPM1.
Cellular localizationNucleus > nucleolus. Cytoplasm. Concentrated in the nucleolus during interphase and distributed in the perichromosome and cytoplasm during mitosis.