Methylthiotransferase that catalyzes the conversion of N6-(dimethylallyl)adenosine (i(6)A) to 2-methylthio-N6-(dimethylallyl)adenosine (ms(2)i(6)A) at position 37 (adjacent to the 3'-end of the anticodon) of four mitochondrial DNA-encoded tRNAs (Ser(UCN), Phe, Tyr and Trp) ( ). Essential for efficient and highly accurate protein translation by the ribosome ( ). Specifically inhibits CDK5 activation by CDK5R1 . Essential for efficient mitochondrial protein synthesis and respiratory chain; shows pathological consequences in mitochondrial disease .
Subcellular locations: Mitochondrion
Expressed in heart, brain, placenta, lung, liver, skeletal muscle, kidney and pancreas . Expressed in neurons of central nervous tissue (, ).
Mainly expressed in brain, placenta and testis.
High expression in placenta and lung.