Intracellular mono-ADP-ribosyltransferase that plays a role in different processes, such as protein translation and unfolded protein response (UPR), through the mono-ADP-ribosylation of proteins involved in those processes ( , ). Acts as an inhibitor of protein translation by catalyzing mono-ADP-ribosylation of ribosomal subunits, such as RPL14 and RPS6, thereby inhibiting polysome assembly and mRNA loading . Mono-ADP-ribosylation of ribosomal subunits is promoted by NMNAT2 . Involved in the unfolded protein response (UPR) by ADP-ribosylating and activating EIF2AK3 and ERN1, two important UPR effectors . May also mediate mono-ADP-ribosylation of karyopherin KPNB1 a nuclear import factor . May not modify proteins on arginine or cysteine residues compared to other mono-ADP-ribosyltransferases .
Subcellular locations: Endoplasmic reticulum membrane