RNA-binding domains of RBPs. Often, several RNA-binding domains are found within one RBP. Different RNA-binding domains include the RNA-binding domain (RBD), K-homology (KH) domain, RGG (Arg-Gly-Gly) box, double stranded RNA-binding domain (dsRBD), Piwi/Argonaute/Zwille (PAZ) domain, RNA helicase DEAD/DEAH box, RNA-binding zinc finger (ZnF) and Puf RNA-binding repeats (PUF). All are presented as colored boxes.