Essential for the formation of P-bodies, cytosolic membrane-less ribonucleoprotein granules involved in RNA metabolism through the coordinated storage of mRNAs encoding regulatory functions. Plays a role in P-bodies to coordinate the storage of translationally inactive mRNAs in the cytoplasm and prevent their degradation. ATP + H2O = ADP + H(+) + phosphate Upon cellular stress, relocalizes to stress granules. Belongs to the DEAD box helicase family. DDX6/DHH1 subfamily.