RIOK2

RIOK2 operates in cytoplasmic 40S ribosomal-subunit maturation and, relative to RIOK1, is distinguished by its association with pre-40S intermediates and its interplay with the endonuclease NOB1 during the final cleavage of 18S rRNA. Like the other RIO-family atypical kinases, RIOK2 adopts a divergent catalytic fold and is considered essential for viability of human cells. It is frequently overexpressed in proliferating and transformed cells, and its depletion stalls 18S processing and reduces translational capacity. Recombinant RIOK2 is used to dissect late ribosome-biogenesis steps, to assay atypical kinase activity and to explore RIOK2 as a proliferation-linked target.