RNA-dependent helicase (PubMed:29100085). Plays an important role in the assembly of the mitochondrial large ribosomal subunit (PubMed:25683715, PubMed:29100085). Required for optimal function of the zinc-finger antiviral protein ZC3HAV1 (By similarity). Associates with mitochondrial DNA (PubMed:18063578). Involved in nervous system development and differentiation through its involvement in the up-regulation of a number of genes which are required for neurogenesis, including GSC, NCAM1, neurogenin, and NEUROD (By similarity). ATP + H2O = ADP + H(+) + phosphate Identified in a complex with TFAM and SSBP1. Interacts with AGO1 and AGO2. Interacts (via N-terminus) with ZC3HAV1 (via N-terminal domain) in an RNA-independent manner (By similarity). Found in a complex with GRSF1, DDX28, FASTKD2 and FASTKD5 (PubMed:25683715). Localizes to mitochondrial RNA granules found in close proximity to the mitochondrial nucleoids (PubMed:16825194, PubMed:25683715). Relocalizes to stress granules upon heat stress (PubMed:29100085). Additional isoforms seem to exist. Phosphorylated on Ser-15. The disease is caused by variants affecting the gene represented in this entry. Belongs to the DEAD box helicase family. DEAH subfamily. Extended N-terminus. Probable cloning artifact.