Involved in pre-mRNA splicing as component of the spliceosome. Facilitates nuclear export of spliced mRNA by releasing the RNA from the spliceosome. ATP + H2O = ADP + H(+) + phosphate Identified in the spliceosome C complex. Interacts with ARRB2; the interaction is detected in the nucleus upon OR1D2 stimulation. The RS domain confers a nuclear localization signal, and appears to facilitate the interaction with the spliceosome. Belongs to the DEAD box helicase family. DEAH subfamily. DDX8/PRP22 sub-subfamily.