May be involved in the storage of translationally inactive mRNAs and protect them from degradation (By similarity). Plays a role in control of mRNA translation (By similarity). Component of a ribonucleoprotein (RNP) complex, at least composed of cpeb1, lsm14b/rap55b, ddx6/Xp54, ybx2/frgy2, pat1/P100, eif4enif1/4E-T and eif4e1b. Different translationally-repressed mRNP complexes probably exist that contain either lsm14a/rap55a or lsm14b/rap55b depending on the developmental stage (By similarity). 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. Belongs to the LSM14 family.