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 (PubMed:25995375, PubMed:27342281, PubMed:31422817). Plays a role in P- bodies to coordinate the storage of translationally inactive mRNAs in the cytoplasm and prevent their degradation (PubMed:27342281). In the process of mRNA degradation, plays a role in mRNA decapping (PubMed:16364915). Blocks autophagy in nutrient-rich conditions by repressing the expression of ATG-related genes through degradation of their transcripts (PubMed:26098573). {ECO:0000269|PubMed:16364915, ECO:0000269|PubMed:25995375, ECO:0000269|PubMed:26098573, ECO:0000269|PubMed:27342281, ECO:0000269|PubMed:31422817}. This is the function of DDX6 (DEAD-box helicase 6, ENSG00000110367).