Mono-ADP-ribosyltransferase that mediates mono-ADP-ribosylation of target proteins (PubMed:25043379, PubMed:25673562). Plays a role in nuclear envelope stability and nuclear remodeling during spermiogenesis (By similarity). L-aspartyl-[protein] + NAD(+) = 4-O-(ADP-D-ribosyl)-L-aspartyl-[protein] + nicotinamide L-cysteinyl-[protein] + NAD(+) = H(+) + nicotinamide + S-(ADP-D-ribosyl)-L-cysteinyl-[protein] L-glutamyl-[protein] + NAD(+) = 5-O-(ADP-D-ribosyl)-L-glutamyl-[protein] + nicotinamide L-lysyl-[protein] + NAD(+) = H(+) + N(6)-(ADP-D-ribosyl)-L-lysyl-[protein] + nicotinamide Colocalizes with NUP153 at nuclear pores. Auto-mono-ADP-ribosylated. May be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay. Belongs to the ARTD/PARP family. Truncated N-terminus. Truncated N-terminus.