NAT10 transfers an acetyl group from acetyl coenzyme A to the N4 positions of the residues that will become cytidine 1337 and cytidine-1842 in 18S rRNA (Ito et al. 2014, Sharma et al. 2015). (The point at which NAT10 acts during rRNA nucleolytic processing is unknown.) NAT10 also hydrolyzes ATP, presumably to provide helicase activity for the reaction (Ito et al. 2014, Sharma et al. 2015). NAT10 in a complex with THUMPD1 also acetylates tRNAs, however THUMPD1 is not required for acetylation of rRNA (Sharma et al. 2015).