ATP-dependent RNA helicase that is an integral component of messenger ribonucleoprotein complexes (mRNPs), storage particles that mask maternal mRNAs from the translational apparatus during oocyte maturation. ATP + H2O = ADP + H(+) + phosphate Component of a ribonucleoprotein (RNP) complex, composed at least of cpeb1, lsm14b/rap55b, ddx6/Xp54, ybx2/frgy2, pat1/P100, eif4enif1/4E-T and eif4e1b. Component of a ribonucleoprotein (RNP) complex, composed at least of elavl1/elrA and/or elavl2/elrB, igf2bp3/vg1RBP, ddx6/Xp54, ybx2/frgy2, lsm14b/rap55b and, in a subset of RNP complexes, stau1/staufen. Component of a ribonucleoprotein (RNP) complex, composed at least of lsm14a/rap55a, ybx2/frgy2, ddx6/Xp54 and eif4enif1/4E-T. Interacts with lsm14a/rap55a (By similarity). Mostly cytoplasmic. Upon cellular stress, relocalizes to stress granules. Belongs to the DEAD box helicase family. DDX6/DHH1 subfamily.