ATP-dependent RNA helicase essential for mRNA export from the nucleus. Plays an important role in the positive regulation of CBF/DREB transcription factors. ATP + H2O = ADP + H(+) + phosphate Interacts with NUP214 (via N-terminus). Constitutively expressed. By abscisic acid (ABA). 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. DDX19/DBP5 subfamily.