PAZ domain, Piwi_like subfamily. In multi-cellular organisms, the Piwi protein appears to be essential for the maintenance of germline stem cells. In the Drosophila male germline, Piwi was shown to be involved in the silencing of retrotransposons in the male gametes. The Piwi proteins share their domain architecture with other members of the argonaute family. The PAZ domain has been named after the proteins Piwi, Argonaut, and Zwille. PAZ is found in two families of proteins that are essential components of RNA-mediated gene-silencing pathways, including RNA interference, the Piwi and Dicer families. PAZ functions as a nucleic acid binding domain, with a strong preference for single-stranded nucleic acids (RNA or DNA) or RNA duplexes with single-stranded 3' overhangs. It has been suggested that the PAZ domain provides a unique mode for the recognition of the two 3'-terminal nucleotides in single-stranded nucleic acids and buries the 3' OH group, and that it might recognize characteristic 3' overhangs in siRNAs within RISC (RNA-induced silencing) and other complexes.
Jiyao W et al.(2023). "The conserved domain database in 2023.",