ATP-dependent RNA helicase involved in mRNA turnover, and more specifically in mRNA decapping by activating the decapping enzyme DCP1 (PubMed:11780629, PubMed:12032091, PubMed:11696541, PubMed:12730603, PubMed:15703442. PubMed:15706350). Is involved in G1/S DNA-damage checkpoint recovery, probably through the regulation of the translational status of a subset of mRNAs (PubMed:15166134). May also have a role in translation and mRNA nuclear export (PubMed:12930949). Required for sporulation (PubMed:12930949). Blocks autophagy in nutrient-rich conditions by, at least partly, binding and repressing the expression of a set of ATG genes, including ATG3, ATG7, ATG8, ATG19, ATG20, ATG22 and SNX4/ATG24 (PubMed:26098573). ATP + H2O = ADP + H(+) + phosphate Associated with the CCR4-NOT complex and possibly other big complexes (PubMed:9504907, PubMed:12930949). Interacts with CDC39/NOT1 (PubMed:11696541). Interacts with DCP1, LSM1, and POP2 (PubMed:9504907, PubMed:11780629). Interacts with IGO1 (PubMed:20471941). Interacts with PAT1 and with KEM1, the major 5'-3' exonuclease (PubMed:11780629, PubMed:12032091). The Q motif is unique to and characteristic of the DEAD box family of RNA helicases and controls ATP binding and hydrolysis. Leads to an increased in autophagy flux (PubMed:26098573). Causes an accumulation of ATG3, ATG7, ATG8, ATG19, ATG20, ATG22 and SNX4/ATG24 transcripts in nutrient-replete conditions (PubMed:26098573). Present with 42900 molecules/cell in log phase SD medium. Belongs to the DEAD box helicase family. DDX6/DHH1 subfamily.