Piwi_piwi-like_Euk: PIWI domain, Piwi-like subfamily found in eukaryotes. This domain is found in Piwi and closely related proteins, where it is believed to perform a crucial role in germline cells, via RNA silencing. RNA silencing refers to a group of related gene-silencing mechanisms mediated by short RNA molecules, including siRNAs, miRNAs, and heterochromatin-related guide RNAs. The mechanism in Piwi is believed to be similar to that in Argonaute, the central component of the RNA-induced silencing complex (RISC). The PIWI domain is the C-terminal portion of Argonaute and consists of two subdomains, one of which provides the 5' anchoring of the guide RNA and the other, the catalytic site for slicing.
Jiyao W et al.(2023). "The conserved domain database in 2023.",