Figure S3. PARP1/HPF1 ADP-ribosylation is reduced by PARG but not by MACROD1.

Immunoprecipitated GFP-PARP1 was supplemented with recombinant His-HPF1 and automodified using ³²P-NAD⁺ in an ADP-ribosylation reaction for 30 min. The automodified PARP1 was further incubated alone, with PARGcat or PARGcat and MACROD1. The signal present after PARG and MACROD1 treatment should represent MARylation on serines, which is not reversed by MACROD1.