ATP-dependent RNA helicase which is a core component of a variety of ribonucleoprotein complexes (RNPs) that play critical roles in translational repression and mRNA decapping during embryogenesis, oogenesis, neurogenesis and neurotransmission (PubMed:11546740, PubMed:16256742, PubMed:17178403, PubMed:18590813, PubMed:21267420, PubMed:21447556, PubMed:28875934, PubMed:28388438, PubMed:17982591, PubMed:31114929). Recruits core components and translational repressors to some RNP complexes, and mediates RNP aggregation into processing granules such as P-bodies (PubMed:28875934, PubMed:11546740, PubMed:16256742, PubMed:17178403, PubMed:21267420, PubMed:21447556, PubMed:17982591). As part of a RNP complex containing tral, eIF4E1, cup, and pAbp, involved in RNP-mediated translational repression of maternal mRNAs during oogenesis and embryogenesis (PubMed:28875934). As part of a RNP complex containing tral and the RNA localization factors exu and yps, mediates translational silencing of mRNAs such as osk/oskar and bcd/bicoid during their transport to the oocyte in order to prevent their translation until they reach their positional destinations (PubMed:11546740). In neurons and possibly imaginal disks, involved in miRNA-mediated translational repression, possibly in association with components of the piRNA transposon silencing pathway (PubMed:21447556, PubMed:17178403, PubMed:21267420, PubMed:17982591, PubMed:21081899). Involved in RNA localization and protein trafficking in the oocyte (PubMed:11546740, PubMed:16256742). As part of an ER-associated RNP containing tral, cup and yps, required for tral-dependent ER exit site formation and consequently efficient trafficking of proteins such as grk and yl through the secretory pathway (PubMed:16256742). Component of neuron RNPs that mediate transport and translation of neuronal RNAs, including translation repression of synaptic transcripts in preparation for their dendritic targeting (PubMed:17178403, PubMed:21267420, PubMed:28388438). As part of the Atx2-Not1 repressor complex promotes Not1-dependent post-transcriptional gene silencing in adult circadian pacemaker neurons in order to sustain high-amplitude circadian rhythms and Pdf cycling in a per-independent manner (PubMed:28388438). Promotes the interaction between Atx2 and Not1 within the Atx2-Not1 RNP complex (PubMed:28388438). Recruited to the 4EHP-GYF2 complex by Gyf, where it plays a role in 4EHP-GYF2 mediated translational repression and mRNA decay (PubMed:31114929). ATP + H2O = ADP + H(+) + phosphate Conserved component of different types of multiprotein ribonucleoprotein complexes (RNPs) that form distinct germ granules (P-body, nuage, sponge body or polar granules) and P-body-like neuronal RNPs (PubMed:11546740, PubMed:16256742, PubMed:18765641, PubMed:18590813, PubMed:19285948, PubMed:28388438). Consequently it interacts with a wide variety of proteins, some of which appear to be common interactive partners in almost all RNPs types i.e. cup and tral, whereas other interactions are specific to a germ granule/RNP (PubMed:28945271). Core functional components in me31B-containing RNPs include RNA regulatory proteins (such as translational repressor, RNA-decapping and exonuclease proteins), RNA localization proteins and additional proteins depending on the biological context of the RNPs (PubMed:17178403, PubMed:28945271). In the P-body RNPs, interacts with at least the translation repressor proteins tral, cup and Edc3, and the mRNA localization factor yps (PubMed:16256742, PubMed:18765641, PubMed:18590813, PubMed:19285948). Interaction with tral or Edc3 is required for translation repression and possibly RNA decapping; binding to tral and Edc3 is mutually exclusive (PubMed:18765641, PubMed:19285948). In the nuage and germ plasm polar granule RNPs, interacts with at least tral, cup, and additional proteins required for assembly and function of the germ granules such as tud, vas and aub (PubMed:18765641, PubMed:18590813, PubMed:19285948, PubMed:28945271). Interacts (when dimethylated on Arg residues) with tud; interaction is RNA-independent (PubMed:28945271). Component of the osk RNP complex, which is composed of at least me31B, exu, yps, aret/bruno, cup, and the mRNA of osk (PubMed:10662770). Component of the nos RNP complex, which is composed of at least smg, cup, tral, me31B, the CCR4-NOT complex members Rga/NOT2 and Caf1-55, and the mRNA of nos (PubMed:21081899). Interacts with tral and piRNA pathway components papi and AGO3; promotes interaction between nuage RNPs and the piRNA-mediated transposon silencing (PubMed:21447556). Forms a RNP containing at least me31B, eIF4E1, cup, tral and pAbp; this interaction is required for the translational silencing of maternal mRNAs during the maternal-to-zygotic transition (PubMed:28875934). In the sponge body, forms a RNP containing at least me31B, exu, yps and the mRNA of osk; interactions with exu and yps are RNA dependent (PubMed:11546740). Component of a neuronal RNP, at least composed of me31B, tral and Fmr1 (PubMed:17178403). Component of the Atx2-Not1 repressor complex, composed of at least me31B, Atx2, tyf and pAbp (PubMed:28388438). Interacts (via the C-terminus) with Atx2, tyf, pAbp and Lsm12a (PubMed:28388438). Interacts (via RecA-like domain 2) with 4EHP-GYF2 complex member Gyf (via the me31B binding motif) (PubMed:31114929, PubMed:31439631). Interacts with 4E-T, Edc3 and Patr-1 (PubMed:31439631). Component of a variety of germ granule ribonucleoprotein complexes (RNPs) including the nuage of nurse cells, sponge bodies of nurse cells and early egg chambers in oocytes, as well as polar granules in the germ plasm at the posterior pole of mid-late stage oocytes and in early embryos (PubMed:11546740, PubMed:18590813, PubMed:21447556, PubMed:28945271, PubMed:21267420). Component of an RNP that localizes to discrete subdomains of the ER cytoplasmic surface (PubMed:21267420, PubMed:16256742). Also present in cytoplasmic granules in the cell bodies and neuropil area of the antennal lobes (PubMed:21267420). In the olfactory sensory and projection neurons, granules appear to predominately localize to postsynaptic dendrites (PubMed:21267420). Ubiquitously expressed throughout the brain (at protein level) (PubMed:21267420, PubMed:17178403). Expressed in the olfactory system including the antennal lobes, projection neurons, local interneurons, mushroom-body Kenyon cells and glial cells (at protein level) (PubMed:21267420). First detected at low levels in the germarium region 2B where it is concentrated in the pro-oocytes (at protein level) (PubMed:11546740). Remains concentrated in the oocyte until mid-oogenesis (at protein level) (PubMed:11546740). In early egg chambers detected in nurse cells and oocytes, and later accumulates at the posterior pole of stage 10 oocytes (at protein level) (PubMed:11546740). Expression decreases during the first 5 hours of embryogenesis; expression levels are high during the first 2 hours of embryogenesis then sharply decrease at 2-3 hours and remains low (at protein level) (PubMed:28875934). Ubiquitously expressed in cleavage embryos but is not detected at the cellular blastoderm stage (at protein level) (PubMed:11546740). Expressed both maternally and zygotically (PubMed:1900936). Symmetrically dimethylated on arginine residues. Larvae lethal at the second- or third-instar stage (PubMed:11546740). RNAi-mediated knockdown in adult pigment dispersing factor (Pdf)-expressing clock neurons results in poor circadian locomotor rhythms under constant dark (DD) conditions (PubMed:28388438). The axonal terminus of s-LNv neurons display a loss of Pdf circadian daily oscillations which is consistent with their behavioral arrhythmicity (PubMed:28388438). However, there is no effect on the daily oscillations of pir and tim proteins in Pdf neurons (PubMed:28388438). Double knockdown with Atx2 enhances the behavioral arrhythmicity (PubMed:28388438). RNAi-mediated knockdown in the dorsal-most class IV neurons frequently results in defects in terminal dendrite morphology and dendritic tiling (PubMed:17178403). RNAi-mediated knockdown in adult projection neurons increases levels of the translational reporter protein CaMKII in the antennal lobe (PubMed:21267420). RNAi-mediated knockdown in the anterior/posterior boundary of the wing imaginal disk causes loss of DCP1- and pcm-expressing P-bodies (PubMed:17982591). Belongs to the DEAD box helicase family. DDX6/DHH1 subfamily.