Protein-histidine N-methyltransferase that specifically mediates 3-methylhistidine (tele-methylhistidine) methylation of actin at 'His-73' (  ). Histidine methylation of actin is required for smooth muscle contraction of the laboring uterus during delivery . Does not have protein-lysine N-methyltransferase activity and probably only catalyzes histidine methylation of actin ( ).
Subcellular locations: Cytoplasm, Nucleus
Localizes mainly in the cytoplasm.