Regulator of post-transcriptional mitochondrial gene expression, required for assembly of the mitochondrial ribosome and for recruitment of mRNA and lncRNA. Binds RNAs containing the 14 base G-rich element. Preferentially binds RNAs transcribed from three contiguous genes on the light strand of mtDNA, the ND6 mRNA, and the long non-coding RNAs for MT-CYB and MT-ND5, each of which contains multiple consensus binding sequences. Involved in the degradosome-mediated decay of non-coding mitochondrial transcripts (MT-ncRNA) and tRNA-like molecules. Acts by unwinding G-quadruplex RNA structures in MT-ncRNA, thus facilitating their degradation by the degradosome. G-quadruplexes (G4) are non-canonical 4 stranded structures formed by transcripts from the light strand of mtDNA. Monomer. Found in a complex with DDX28, DHX30, FASTKD2 and FASTKD5. Interacts with the mitochondrial RNase P complex subunit TRMT10C/MRPP1. Interacts with the 2 components of the mitochondrial degradosome complex, PNPT1 and SUPV3L1, in an RNA-dependent manner. Localizes to mitochondrial RNA granules found in close proximity to the mitochondrial nucleoids. The RRM domains mediate RNA-binding.