Mitochondrial ribosome (mitoribosome) assembly factor (PubMed:36482135, PubMed:38199006). Binds at the interface of the head and body domains of the mitochondrial small ribosomal subunit (mt-SSU), occluding the mRNA channel and preventing compaction of the head domain towards the body (PubMed:36482135). Probable inactive methyltransferase: retains the characteristic folding and ability to bind S-adenosyl-L-methionine, but it probably lost its methyltransferase activity (PubMed:38234605).