ATP-binding RNA helicase required during spermatogenesis (PubMed:28536242). Required to repress transposable elements and prevent their mobilization, which is essential for the germline integrity. Acts via the piRNA metabolic process, which mediates the repression of transposable elements during meiosis by forming complexes composed of piRNAs and Piwi proteins and governs the methylation and subsequent repression of transposons. Acts downstream of piRNA biogenesis: exclusively required for transposon silencing in the nucleus, suggesting that it acts as a nuclear effector in the nucleus together with PIWIL4. ATP + H2O = ADP + H(+) + phosphate Interacts with piRNA-associated proteins PIWIL1 and PIWIL4. Component of the nuage, also named P granule, a germ-cell-specific organelle required to repress transposon activity during meiosis. Specifically localizes to piP-bodies, a subset of the nuage which contains secondary piRNAs. PIWIL2 is required for its localization to piP-bodies. The disease is caused by variants affecting the gene represented in this entry. Belongs to the DEAD box helicase family. DEAH subfamily. Truncated N-terminus.