Discovery of reversing enzymes for RNA ADP-ribosylation reveals a possible defence module against toxic attack

Lu, Yang; Schuller, Marion; Bullen, Nathan P; Mikolčević, Petra; Zonjić, Iva; Raggiaschi, Roberto; Mikoč, Andreja; Whitney, John C; Ahel, Ivan (2025) Discovery of reversing enzymes for RNA ADP-ribosylation reveals a possible defence module against toxic attack. Nucleic Acids Research, 53 (4). ISSN 0305-1048

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Abstract

Nucleic acid ADP-ribosylation and its associated enzymes involved in catalysis and hydrolysis are widespread among all kingdoms of life. Yet, its roles in mammalian and bacterial physiology including inter-/intraspecies conflicts are currently underexplored. Recently, several examples of enzymatic systems for RNA ADP-ribosylation have been identified, showing that all major types of RNA species, including messenger RNA, ribosomal RNA, and transfer RNA, can be targeted by ADP-ribosyltransferases (ARTs) which attach ADP-ribose modifications either to nucleobases, the backbone ribose, or phosphate ends. Yet little is known about the reversibility of RNA ADP-ribosylation by ADP-ribosylhydrolases belonging to the macrodomain, ARH, or NADAR superfamilies. Here, we characterize the hydrolytic activity of ADP-ribosylhydrolases on RNA species ADP-ribosylated by mammalian and bacterial ARTs. We demonstrate that NADAR ADP-ribosylhydrolases are the only hydrolase family able to reverse guanosine RNA base ADP-ribosylation while they are inactive on phosphate-end RNA ADP-ribosylation. Furthermore, we reveal that macrodomain-containing PARG enzymes are the only hydrolase type with the ability for specific and efficient reversal of 2′-hydroxyl group RNA ADP-ribosylation catalysed by Pseudomonas aeruginosa effector toxin RhsP2. Moreover, using the RhsP2/bacterial PARG system as an example, we demonstrate that PARG enzymes can act as protective immunity enzymes against antibacterial RNA-targeting ART toxins.

Item Type:	Article
Uncontrolled Keywords:	ADP-riosylation; RNA modification; bacterial toxins
Subjects:	NATURAL SCIENCES > Biology NATURAL SCIENCES > Biology > Biochemistry and Molecular Biology
Divisions:	Division of Molecular Biology
Depositing User:	Petra Mikolčević
Date Deposited:	12 Dec 2025 11:53
URI:	http://fulir.irb.hr/id/eprint/10427
DOI:	10.1093/nar/gkaf069

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