Component of P-granules which is required for P-granule formation and integrity in adult germ cells (PubMed:18234720). Promotes the accumulation of glh-1 mRNA and localization of pgl-1 to P-granules (PubMed:18234720). Involved in RNA-mediated gene silencing (RNAi) in the germline (PubMed:18234720, PubMed:32843637). In particular, it is required for piwi-interacting RNA (piRNA) gene silencing and positively regulates the formation of secondary 22G-RNAs, which are RNA-dependent RNA polymerase-derived endo-siRNAs, typically 22 nucleotides in length with a 5'guanosine residue (PubMed:32843637). Its role in RNAi may also be through positively regulating the expression of the dsRNA-binding protein rde-4 (PubMed:18234720). Plays a role in small RNA-directed transgenerational epigenetic inheritance (PubMed:27015309, PubMed:29769721). Interacts (via N-terminus) with prg-1; the interaction is direct (PubMed:32843637). May interact with edg-1 (PubMed:32843637). Localizes to P-granules in germ cells at all stages of development (PubMed:18234720). Co-localizes with prg-1 at peri-nuclear P-granules in the proliferative zone and transition zone, at pachytene, in oocytes and in embryos (PubMed:32843637). In the distal loop, a higher proportion of deps-1 than prg-1 dissociates from the perinuclear region (PubMed:32843637). In the adult germline, co-localizes with znfx-1 at P-granules and with pgl-1 at P-granules in the pachytene region (PubMed:32843637). Expressed in germ cells. Expressed at all stages of development from embryogenesis to adulthood (PubMed:18234720). Expressed at all embryonic stages (PubMed:18234720). RNAi-mediated knockdown results in sterility and disrupts the localization of pgl-1 to P-granules at 24.5 degrees Celsius.