RNA-dependent helicase (By similarity). Plays an important role in the assembly of the mitochondrial large ribosomal subunit (By similarity). Associates with mitochondrial DNA (By similarity). Required for optimal function of the zinc-finger antiviral protein ZC3HAV1 (PubMed:21204022). 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 (By similarity). Interacts (via N-terminus) with ZC3HAV1 (via N-terminal domain) in an RNA-independent manner. Found in a complex with GRSF1, DDX28, FASTKD2 and FASTKD5 (By similarity). Localizes to mitochondrial RNA granules found in close proximity to the mitochondrial nucleoids. Relocalizes to stress granules upon heat stress. Belongs to the DEAD box helicase family. DEAH subfamily.