ATP-dependent RNA helicase. Core component of the splicing-dependent multiprotein exon junction complex (EJC) deposited at splice junctions on mRNAs. The EJC is a dynamic structure consisting of core proteins and several peripheral nuclear and cytoplasmic associated factors that join the complex only transiently either during EJC assembly or during subsequent mRNA metabolism. The EJC marks the position of the exon-exon junction in the mature mRNA for the gene expression machinery and the core components remain bound to spliced mRNAs throughout all stages of mRNA metabolism thereby influencing downstream processes including nuclear mRNA export, subcellular mRNA localization, translation efficiency and nonsense-mediated mRNA decay (NMD). Its RNA-dependent ATPase and RNA-helicase activities are induced by MLN51/CASC3, but abolished in presence of the MAGO-Y14 heterodimer, thereby trapping the ATP-bound EJC core onto spliced mRNA in a stable conformation. The inhibition of ATPase activity by the MAGO-Y14 heterodimer increases the RNA-binding affinity of the EJC (By similarity). EJC core proteins play essential roles in rice development, growth and reproduction. Regulates the splicing of UDT1 (UNDEVELOPED TAPETUM 1) pre-mRNA transcript. UDT1 is a key regulator in stamen development (PubMed:27071313). ATP + H2O = ADP + H(+) + phosphate Interacts with MAGO1 and Y14B. Nucleocytoplasmic shuttling protein. Travels to the cytoplasm as part of the exon junction complex (EJC) bound to mRNA. Expressed in roots, leaves, flowers and seeds. The Q motif is unique to and characteristic of the DEAD box family of RNA helicases and controls ATP binding and hydrolysis. Belongs to the DEAD box helicase family. DDX48/FAL1 subfamily.