Partner-binding domain of the endoribonuclease Dicer
The endoribonuclease Dicer plays a central role in RNA interference by breaking down RNA molecules into fragments of about 22 nucleotides (miRNAs and siRNAs). Loading of RNA onto Dicer and the enzymatic cleavage are supported by dsRNA-binding proteins, including trans-activation response (TAR) RNA-binding protein (TRBP) or protein activator of PKR (PACT). Together with Argonaute, this constitutes the RNA-induced silencing complex (RISC) which functions to load the small RNA fragments onto Argonaute. The Partner-binding domain of Dicer is responsible for interactions with the dsRNA-binding proteins. This helical domain can be found inserted in a subset of SF2-type DEAD-box related helicases.