1. Biochemistry and Chemical Biology
  2. Cell Biology
Download icon

SPRTN is a mammalian DNA-binding metalloprotease that resolves DNA-protein crosslinks

  1. Jaime Lopez-Mosqueda
  2. Karthik Maddi
  3. Stefan Prgomet
  4. Sissy Kalayil
  5. Ivana Marinovic-Terzic
  6. Janos Terzic
  7. Ivan Dikic  Is a corresponding author
  1. Goethe University School of Medicine, Germany
  2. University of Split, Croatia
Research Article
  • Cited 68
  • Views 4,223
  • Annotations
Cite this article as: eLife 2016;5:e21491 doi: 10.7554/eLife.21491

Abstract

Ruijs-Aalfs syndrome is a segmental progeroid syndrome resulting from mutations in the SPRTN gene. Cells derived from patients with SPRTN mutations elicit genomic instability and persons afflicted with this syndrome developed hepatocellular carcinoma. Here we describe the molecular mechanism by which SPRTN contributes to genome stability and normal cellular homeostasis. We show that SPRTN is a DNA-dependent mammalian protease required for resolving cytotoxic DNA-protein crosslinks (DPCs); a function that had only been attributed to the metalloprotease Wss1 in budding yeast. We provide genetic evidence that SPRTN and Wss1 function distinctly in vivo to resolve DPCs. Upon DNA or ubiquitin binding, SPRTN can elicit proteolytic activity; cleaving DPC substrates or itself. SPRTN null cells or cells derived from patients with Ruijs-Aalfs syndrome are impaired in the resolution of covalent DPCs in vivo. Collectively, SPRTN is a mammalian protease required for resolving DNA-protein crosslinks in vivo whose function is compromised in Ruijs-Aalfs syndrome patients.

Article and author information

Author details

  1. Jaime Lopez-Mosqueda

    Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0301-1971
  2. Karthik Maddi

    Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
    Competing interests
    No competing interests declared.
  3. Stefan Prgomet

    Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
    Competing interests
    No competing interests declared.
  4. Sissy Kalayil

    Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
    Competing interests
    No competing interests declared.
  5. Ivana Marinovic-Terzic

    Department of Immunology and Medical Genetics, School of Medicine, University of Split, Split, Croatia
    Competing interests
    No competing interests declared.
  6. Janos Terzic

    Department of Immunology an Medical Genetics, School of Medicine, University of Split, Split, Croatia
    Competing interests
    No competing interests declared.
  7. Ivan Dikic

    Institute of Biochemistry II, Goethe University School of Medicine, Frankfurt am Main, Germany
    For correspondence
    dikic@biochem2.uni-frankfurt.de
    Competing interests
    Ivan Dikic, Senior editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8156-9511

Funding

Deutsche Forschungsgemeinschaft (SFB1177)

  • Ivan Dikic

Deutsche Forschungsgemeinschaft (CEF-MC)

  • Ivan Dikic

Human Frontier Science Program (Postdoctoral fellowship)

  • Jaime Lopez-Mosqueda

LOEWE Zentrum CGT and Loewe Network Ub Net (Fellowships)

  • Ivan Dikic

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Wade Harper, Harvard Medical School, United States

Publication history

  1. Received: September 14, 2016
  2. Accepted: November 15, 2016
  3. Accepted Manuscript published: November 17, 2016 (version 1)
  4. Version of Record published: November 29, 2016 (version 2)

Copyright

© 2016, Lopez-Mosqueda et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 4,223
    Page views
  • 808
    Downloads
  • 68
    Citations

Article citation count generated by polling the highest count across the following sources: Scopus, Crossref, PubMed Central.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Further reading

    1. Biochemistry and Chemical Biology
    2. Structural Biology and Molecular Biophysics
    Jing Li et al.
    Research Article

    Integrin conformational ensembles contain two low-affinity states, bent-closed and extended-closed, and an active, high-affinity, extended-open state. It is widely thought that integrins must be activated before they bind ligand; however, one model holds that activation follows ligand binding. As ligand-binding kinetics are not only rate limiting for cell adhesion but also have important implications for the mechanism of activation, we measure them here for integrins α4β1 and α5β1 and show that the low-affinity states bind substantially faster than the high-affinity state. On and off-rates are similar for integrins on cell surfaces and as ectodomain fragments. Although the extended-open conformation's on-rate is ~20-fold slower, its off-rate is ~25,000-fold slower, resulting in a large affinity increase. The tighter ligand-binding pocket in the open state may slow its on-rate. Low affinity integrin states not only bind ligand more rapidly, but are also more populous on the cell surface than high affinity states. Thus, our results suggest that integrin binding to ligand may precede, rather than follow, activation by 'inside-out signaling'.

    1. Biochemistry and Chemical Biology
    2. Cell Biology
    Aixin Song et al.
    Research Article Updated

    UCH37, also known as UCHL5, is a highly conserved deubiquitinating enzyme (DUB) that associates with the 26S proteasome. Recently, it was reported that UCH37 activity is stimulated by branched ubiquitin (Ub) chain architectures. To understand how UCH37 achieves its unique debranching specificity, we performed biochemical and Nuclear Magnetic Resonance (NMR) structural analyses and found that UCH37 is activated by contacts with the hydrophobic patches of both distal Ubs that emanate from a branched Ub. In addition, RPN13, which recruits UCH37 to the proteasome, further enhances branched-chain specificity by restricting linear Ub chains from having access to the UCH37 active site. In cultured human cells under conditions of proteolytic stress, we show that substrate clearance by the proteasome is promoted by both binding and deubiquitination of branched polyubiquitin by UCH37. Proteasomes containing UCH37(C88A), which is catalytically inactive, aberrantly retain polyubiquitinated species as well as the RAD23B substrate shuttle factor, suggesting a defect in recycling of the proteasome for the next round of substrate processing. These findings provide a foundation to understand how proteasome degradation of substrates modified by a unique Ub chain architecture is aided by a DUB.