Plays an essential role in mitochondrial ribosome biogenesis. As a component of a functional protein-RNA module, consisting of RCC1L, NGRN, RPUSD3, RPUSD4, TRUB2, FASTKD2 and 16S mitochondrial ribosomal RNA (16S mt-rRNA), controls 16S mt-rRNA abundance and is required for intra-mitochondrial translation of core subunits of the oxidative phosphorylation system. Forms a regulatory protein-RNA complex, consisting of RCC1L, NGRN, RPUSD3, RPUSD4, TRUB2, FASTKD2 and 16S mt-rRNA. Interacts with 16S mt-rRNA; this interaction is direct. Expressed at high levels in heart, brain and skeletal muscle. In brain, mainly expressed in neurons rather than glial cells. Highly up-regulated in neuroblastostoma cells by retinoic acid treatment inducing neurite outgrowth. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the neugrin family. Wrong choice of CDS. Wrong choice of CDS. Wrong choice of CDS. Wrong choice of CDS. Wrong choice of CDS. Wrong choice of CDS. Wrong choice of CDS. Wrong choice of CDS. N-terminus does not match isoform 2. Wrong choice of CDS. Wrong choice of CDS.