As a component of the mitochondrial large ribosomal subunit, it plays a role in mitochondrial translation. Associates with mitochondrial RNA polymerase to activate transcription. Component of the mitochondrial ribosome large subunit (39S) which comprises a 16S rRNA and about 50 distinct proteins (By similarity). Interacts with NOA1. Belongs to the bacterial ribosomal protein bL12 family.