2. Academic Validation
  3. Neuropathic MORC2 mutations perturb GHKL ATPase dimerization dynamics and epigenetic silencing by multiple structural mechanisms

Neuropathic MORC2 mutations perturb GHKL ATPase dimerization dynamics and epigenetic silencing by multiple structural mechanisms

  • Nat Commun. 2018 Feb 13;9(1):651. doi: 10.1038/s41467-018-03045-x.
Christopher H Douse 1,  Stuart Bloor 2,  Yangci Liu 3,  Maria Shamin 3,  Iva A Tchasovnikarova 2 4,  Richard T Timms 2 5,  Paul J Lehner 2,  Yorgo Modis 6
Affiliations

Affiliations

  • 1 Department of Medicine, MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0QH, UK. cdouse@mrc-lmb.cam.ac.uk.
  • 2 Department of Medicine, Cambridge Institute for Medical Research, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0XY, UK.
  • 3 Department of Medicine, MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0QH, UK.
  • 4 Department of Molecular Biology, Massachusetts General Hospital, and Department of Genetics, Harvard Medical School, Boston, MA, 02114, USA.
  • 5 Department of Medicine, Brigham and Women's Hospital, Boston, MA, 02115, USA.
  • 6 Department of Medicine, MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, University of Cambridge, Cambridge, CB2 0QH, UK. ymodis@mrc-lmb.cam.ac.uk.
PMID: 29440755 DOI: 10.1038/s41467-018-03045-x
Abstract

Missense mutations in MORC2 cause neuropathies including spinal muscular atrophy and Charcot-Marie-Tooth disease. We recently identified MORC2 as an effector of epigenetic silencing by the human silencing hub (HUSH). Here we report the biochemical and cellular activities of MORC2 variants, alongside crystal structures of wild-type and neuropathic forms of a human MORC2 fragment comprising the GHKL-type ATPase module and CW-type zinc finger. This fragment dimerizes upon binding ATP and contains a hinged, functionally critical coiled-coil insertion absent in other GHKL ATPases. We find that dimerization and DNA binding of the MORC2 ATPase module transduce HUSH-dependent silencing. Disease mutations change the dynamics of dimerization by distinct structural mechanisms: destabilizing the ATPase-CW module, trapping the ATP lid, or perturbing the dimer interface. These defects lead to the modulation of HUSH function, thus providing a molecular basis for understanding MORC2-associated neuropathies.

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