RNA-dependent helicase (PubMed:25219788). Plays an important role in the assembly of the mitochondrial large ribosomal subunit (By similarity). Required for optimal function of the zinc-finger antiviral protein ZC3HAV1 (By similarity). Associates with mitochondrial DNA (By similarity). 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 (PubMed:25219788). ATP + H2O = ADP + H(+) + phosphate Identified in a complex with TFAM and SSBP1. 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. Localizes to mitochondrial RNA granules found in close proximity to the mitochondrial nucleoids. Relocalizes to stress granules upon heat stress. Expressed in the heart, brain, spleen, lung, liver, skeletal muscle, kidney, and testis. Expression is strongest in the testis and brain, while the lowest levels of expression are found in the spleen and lung. Detected at low levels of expression at 3.5 and 6.5 days post coitum (dpc). At 7.5 dpc, it is detected in the ectoderm, mesoderm, and ectoplacental cone. By 8.5 dpc, expression is increased, specifically in the central nervous system, neural plate, and neural tube, which remains constant until 10.5 dpc where it decreases. By 11.5 to 15.5 dpc, expression is reduced further in the central nervous system. Phosphorylated on Ser-15. Belongs to the DEAD box helicase family. DEAH subfamily.