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 in heart, brain, liver and kidney. In brain, mainly expressed in neurons rather than glial cells. Level of expression increases with embryonal development. Highly up-regulated in neuroblastostoma cells by RA and MG132 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. Truncated N-terminus. The N-terminus contains a duplicated region of sequence. Wrong choice of CDS. Truncated N-terminus. Wrong choice of CDS.