Weixler Lisa, Žaja Roko, Ikenga Nonso J, Siefert Jonas, Mohan Ganga, Aydin Gülcan, Wijngaarden Sven, Filippov Dmitri V, Lüscher Bernhard, Feijs-Žaja Karla L H
Institute of Biochemistry and Molecular Biology, Pauwelsstraße 30, RWTH Aachen University, Aachen, Germany.
Institute for Clinical Chemistry and Clinical Pharmacology, Venusberg-Campus 1, University Hospital Bonn, Bonn, Germany.
Commun Biol. 2025 Mar 18;8(1):453. doi: 10.1038/s42003-025-07901-7.
ADP-ribosylation is well-known as protein posttranslational modification and was recently also identified as RNA posttranscriptional modification. When macrodomain proteins were identified as protein ADP-ribosylhydrolases, several ADP-ribosylation substrates were not yet identified. Therefore, the majority of macrodomain-containing proteins have not been tested towards these additional substrates and were considered to be inactive. Here, we compare in vitro activities of the human macrodomains on a range of ADP-ribosylated substrates. We confirm recent findings that PARP9macro1 and PARP14macro1 can remove ADP-ribose from acidic residues and provide evidence that also PARP14macro2 and PARP15macro2 can function as ADP-ribosylhydrolases. In addition, we find that both PARP9macro1 and PARP14macro1 are active as ADPr-RNA decapping protein domains. Notwithstanding these in vitro activities, our data furthermore indicate that in HEK293 cells, PARG is the major ADPr-RNA decapping enzyme. Our findings thus expand the spectrum of known catalytic activities of human macrodomains and demonstrate their different efficiencies towards nucleic acid substrates.
ADP-核糖基化作为一种蛋白质翻译后修饰广为人知，最近它也被鉴定为一种RNA转录后修饰。当巨结构域蛋白被鉴定为蛋白质ADP-核糖水解酶时，一些ADP-核糖基化底物尚未被确定。因此，大多数含巨结构域的蛋白质尚未针对这些额外的底物进行测试，被认为是无活性的。在此，我们比较了人类巨结构域在一系列ADP-核糖基化底物上的体外活性。我们证实了最近的发现，即PARP9macro1和PARP14macro1可以从酸性残基上移除ADP-核糖，并提供证据表明PARP14macro2和PARP15macro2也可以作为ADP-核糖水解酶发挥作用。此外，我们发现PARP9macro1和PARP14macro1作为ADPr-RNA去帽蛋白结构域均具有活性。尽管有这些体外活性，但我们的数据进一步表明，在HEK293细胞中，PARG是主要的ADPr-RNA去帽酶。因此，我们的发现扩展了人类巨结构域已知催化活性的范围，并证明了它们对核酸底物的不同效率。
