ADP-ribosylhydrolase that preferentially hydrolyzes the scissile alpha-O-linkage attached to the anomeric C1” position of ADP-ribose and acts on different substrates, such as proteins ADP-ribosylated on serine and threonine, free poly(ADP-ribose) and O-acetyl-ADP-D-ribose (PubMed:21498885, PubMed:29907568, PubMed:30045870, PubMed:30401461, PubMed:30830864, PubMed:33186521, PubMed:33769608, PubMed:33894202, PubMed:34019811, PubMed:34321462, PubMed:34479984, PubMed:34625544). Specifically acts as a serine mono-ADP-ribosylhydrolase by mediating the removal of mono-ADP-ribose attached to serine residues on proteins, thereby playing a key role in DNA damage response (PubMed:28650317, PubMed:29234005, PubMed:30045870, PubMed:33186521, PubMed:34019811, PubMed:34625544). Serine ADP-ribosylation of proteins constitutes the primary form of ADP-ribosylation of proteins in response to DNA damage (PubMed:29480802, PubMed:33186521, PubMed:34625544). Does not hydrolyze ADP-ribosyl-arginine, -cysteine, -diphthamide, or -asparagine bonds (PubMed:16278211, PubMed:33769608). Also able to degrade protein free poly(ADP-ribose), which is synthesized in response to DNA damage: free poly(ADP-ribose) acts as a potent cell death signal and its degradation by ADPRHL2 protects cells from poly(ADP-ribose)-dependent cell death, a process named parthanatos (PubMed:16278211). Also hydrolyzes free poly(ADP-ribose) in mitochondria (PubMed:22433848). Specifically digests O-acetyl-ADP-D-ribose, a product of deacetylation reactions catalyzed by sirtuins (PubMed:17075046, PubMed:21498885). Specifically degrades 1”-O-acetyl-ADP-D-ribose isomer, rather than 2”-O-acetyl-ADP-D-ribose or 3”-O-acetyl-ADP-D-ribose isomers (PubMed:21498885).
