Probable RNA helicase. Required for miRNA-mediated gene silencing by the RNA-induced silencing complex (RISC). Required for both miRNA-mediated translational repression and miRNA-mediated cleavage of complementary mRNAs by RISC (By similarity). In cooperation with FMR1, regulates miRNA-mediated translational repression by AGO2 (By similarity). Restricts retrotransposition of long interspersed element-1 (LINE-1) in cooperation with TUT4 and TUT7 counteracting the RNA chaperonne activity of L1RE1. Facilitates LINE-1 uridylation by TUT4 and TUT7 (By similarity). Required for embryonic viability and for normal central nervous system development and function. Plays two critical roles in early brain development: suppresses retroelements in the nucleus by directly inhibiting cDNA synthesis, while regulates cytoskeletal mRNAs to influence neurite outgrowth in the cytosol (PubMed:28662698). May function as a messenger ribonucleoprotein (mRNP) clearance factor (By similarity). ATP + H2O = ADP + H(+) + phosphate Interacts with DICER1, AGO2, TARBP2, EIF6 and RPL7A (60S ribosome subunit); they form a large RNA-induced silencing complex (RISC). Interacts with APOBEC3G in an RNA-dependent manner. Interacts with TRIM71 (via NHL repeats) in an RNA-dependent manner (PubMed:28662698) (By similarity). Interacts with both protein products of LIRE1, ORF1p and ORF2p (PubMed:28662698). Interacts with TUT4 and, to a lesser extent, TUT7; the interactions are RNA-dependent. Interacts with AGO2, TNRC6B and UPF1; the interactions are direct and RNA-dependent. Interacts with FMR1; this interaction is direct, occurs in an RNA-dependent manner on polysomes and induces association of MOV10 with RNAs (By similarity). Interacts with SHFL; the interaction increases in presence of RNA (By similarity). Interacts with DHX34; the interaction is RNA-independent (By similarity). In young mouse (P2) neurons, localizes both in nucleus and cytoplasm, but in the adulthood it is only cytoplasmic (PubMed:28662698). Co-enriched in cytoplasmic foci with TUT4 (By similarity). As early as embryonic day 18, there is a higher level of expression in the whole brain compared to adults. Expression continues to rise at birth (P0) and remains elevated over adult levels until P10-P14, when it begins to decline (PubMed:28662698). Highly expressed throughout the P1 brain, including the cortex, hippocampus, cerebellum, midbrain, and hindbrain, there is very little expression in the adult brain except in the hippocampus (PubMed:28662698). Knockout leads to early embryonic lethality. Belongs to the DNA2/NAM7 helicase family. SDE3 subfamily.