Ubiquitin Modification by the E3 Ligase/ADP-Ribosyltransferase Dtx3L/Parp9

  • Mol Cell. 2017 May 18;66(4):503-516.e5. doi: 10.1016/j.molcel.2017.04.028.
Chun-Song Yang  1 ,  Kasey Jividen  1 ,  Adam Spencer  1 ,  Natalia Dworak  1 ,  Li Ni  1 ,  Luke T Oostdyk  2 ,  Mandovi Chatterjee  1 ,  Beata Kuśmider  1 ,  Brian Reon  3 ,  Mahmut Parlak  4 ,  Vera Gorbunova  5 ,  Tarek Abbas  6 ,  Erin Jeffery  7 ,  Nicholas E Sherman  7 ,  Bryce M Paschal  8
Affiliations
  • 1. Center for Cell Signaling, University of Virginia, West Complex, 1335 Lee Street, Charlottesville, VA 22908, USA.
  • 2. Center for Cell Signaling, University of Virginia, West Complex, 1335 Lee Street, Charlottesville, VA 22908, USA; Department of Biochemistry and Molecular Genetics, University of Virginia, PO Box 800733, Charlottesville, VA 22908, USA.
  • 3. Department of Biochemistry and Molecular Genetics, University of Virginia, PO Box 800733, Charlottesville, VA 22908, USA.
  • 4. Department of Radiation Oncology, University of Virginia, PO Box 800383, Charlottesville, VA 22908, USA.
  • 5. Department of Biology, University of Rochester, 434 Hutchison Hall, Rochester, NY 14627, USA.
  • 6. Center for Cell Signaling, University of Virginia, West Complex, 1335 Lee Street, Charlottesville, VA 22908, USA; Department of Biochemistry and Molecular Genetics, University of Virginia, PO Box 800733, Charlottesville, VA 22908, USA; Department of Radiation Oncology, University of Virginia, PO Box 800383, Charlottesville, VA 22908, USA.
  • 7. W. M. Keck Biomedical Mass Spectrometry Laboratory, University of Virginia, Pinn Hall, Room 1034, Charlottesville, VA 22908, USA.
  • 8. Center for Cell Signaling, University of Virginia, West Complex, 1335 Lee Street, Charlottesville, VA 22908, USA; Department of Biochemistry and Molecular Genetics, University of Virginia, PO Box 800733, Charlottesville, VA 22908, USA. Electronic address: [email protected].
PMID: 28525742 DOI: 10.1016/j.molcel.2017.04.028
Abstract

ADP-ribosylation of proteins is emerging as an important regulatory mechanism. Depending on the family member, ADP-ribosyltransferases either conjugate a single ADP-ribose to a target or generate ADP-ribose chains. Here we characterize Parp9, a mono-ADP-ribosyltransferase reported to be enzymatically inactive. Parp9 undergoes heterodimerization with Dtx3L, a histone E3 Ligase involved in DNA damage repair. We show that the Dtx3L/Parp9 heterodimer mediates NAD+-dependent mono-ADP-ribosylation of ubiquitin, exclusively in the context of ubiquitin processing by E1 and E2 Enzymes. Dtx3L/Parp9 ADP-ribosylates the carboxyl group of Ub Gly76. Because Gly76 is normally used for Ub conjugation to substrates, ADP-ribosylation of the Ub carboxyl terminus precludes ubiquitylation. Parp9 ADP-ribosylation activity therefore restrains the E3 function of Dtx3L. Mutation of the NAD+ binding site in Parp9 increases the DNA repair activity of the heterodimer. Moreover, poly(ADP-ribose) binding to the Parp9 macrodomains increases E3 activity. Dtx3L heterodimerization with Parp9 enables NAD+ and poly(ADP-ribose) regulation of E3 activity.

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