Endoribonuclease. (Microbial infection) Required for the initial stages of clathrin-mediated endocytic uptake of a diverse set of flaviviruses, including dengue and West Nile (PubMed:26056282). Not required for clathrin-mediated endocytosis and macropinocytosis (PubMed:26056282). Belongs to the RNase K family.