Component of the mitochondrial large ribosomal subunit (mt-LSU) (PubMed:25278503, PubMed:25838379, PubMed:28892042, PubMed:33602856). Within the mitochondrial ribosomes, required to direct the nascent polypeptide toward the tunnel exit and position the exit at a distance from the membrane surface (PubMed:33602856).
