1. Biochemistry and Chemical Biology
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An acquired scaffolding function of the DNAJ-PKAc fusion contributes to oncogenic signaling in fibrolamellar carcinoma

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Cite this article as: eLife 2019;8:e44187 doi: 10.7554/eLife.44187

Abstract

Fibrolamellar carcinoma (FLC) is a rare liver cancer. FLCs uniquely produce DNAJ-PKAc, a chimeric enzyme consisting of a chaperonin-binding domain fused to the Ca subunit of protein kinase A. Biochemical analyses of clinical samples reveal that a unique property of this fusion enzyme is the ability to recruit heat shock protein 70 (Hsp70). This cellular chaperonin is frequently up-regulated in cancers. Gene-editing of mouse hepatocytes generated disease-relevant AML12DNAJ-PKAc cell lines. Further analyses indicate that the proto-oncogene A-kinase anchoring protein-Lbc is up-regulated in FLC and functions to cluster DNAJ-PKAc/Hsp70 sub-complexes with a RAF-MEK-ERK kinase module. Drug screening reveals Hsp70 and MEK inhibitor combinations that selectively block proliferation of AML12DNAJ-PKAc cells. Phosphoproteomic profiling demonstrates that DNAJ-PKAc biases the signaling landscape toward ERK activation and engages downstream kinase cascades. Thus, the oncogenic action of DNAJ-PKAc involves an acquired scaffolding function that permits recruitment of Hsp70 and mobilization of local ERK signaling.

Article and author information

Author details

  1. Rigney E Turnham

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. F Donelson Smith

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8080-7589
  3. Heidi L Kenerson

    Department of Surgery, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Mitchell H Omar

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Martin Golkowski

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Irvin Garcia

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Renay Bauer

    Department of Surgery, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Ho-Tak Lau

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Kevin M Sullivan

    Department of Surgery, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  10. Lorene K Langeberg

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3760-7813
  11. Shao-En Ong

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  12. Kimberly J Riehle

    Department of Surgery, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  13. Raymond S Yeung

    Department of Surgery, University of Washington Medical Center, Seattle, United States
    Competing interests
    The authors declare that no competing interests exist.
  14. John D Scott

    Department of Pharmacology, University of Washington Medical Center, Seattle, United States
    For correspondence
    scottjdw@uw.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0367-8146

Funding

National Institute of Diabetes and Digestive and Kidney Diseases (R01DK119192)

  • John D Scott

Fibrolamellar Cancer Foundation

  • John D Scott

National Cancer Institute (R21CA201867)

  • Kimberly J Riehle

St. Baldrick's Foundation

  • Kimberly J Riehle

National Cancer Institute (R21CA177402)

  • Shao-En Ong

NIH Office of the Director (S10 OD021502)

  • Shao-En Ong

National Institutes of Health (2T32CA080416)

  • Rigney E Turnham

National Institute of Diabetes and Digestive and Kidney Diseases (F32DK121415)

  • Mitchell H Omar

Fibrolamellar Cancer Foundation

  • Raymond S Yeung

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

Reviewing Editor

  1. Roger J Davis, University of Massachusetts Medical School, United States

Publication history

  1. Received: December 6, 2018
  2. Accepted: May 5, 2019
  3. Accepted Manuscript published: May 7, 2019 (version 1)
  4. Version of Record published: May 23, 2019 (version 2)

Copyright

© 2019, Turnham 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.

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