1. Biochemistry and Chemical Biology

The Structural Determinants of PH Domain-Mediated Regulation of Akt Revealed by Segmental Labeling

  1. Nam Chu
  2. Thibault Viennet
  3. Hwan Bae
  4. Antonieta Salguero
  5. Andras Boeszoermenyi
  6. Haribabu Arthanari  Is a corresponding author
  7. Philip A Cole  Is a corresponding author
  1. Harvard Medical School, Brigham and Women's Hospital, United States
  2. Harvard Medical School, Dana-Farber Cancer Institute, United States
  3. Harvard Medical School, United States
https://doi.org/10.7554/eLife.59151
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  1. Nam Chu
  2. Thibault Viennet
  3. Hwan Bae
  4. Antonieta Salguero
  5. Andras Boeszoermenyi
  6. Haribabu Arthanari
  7. Philip A Cole
(2020)
The Structural Determinants of PH Domain-Mediated Regulation of Akt Revealed by Segmental Labeling
eLife 9:e59151.
https://doi.org/10.7554/eLife.59151
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Abstract

Akt is a critical protein kinase that governs cancer cell growth and metabolism. Akt appears to be autoinhibited by an intramolecular interaction between its N-terminal pleckstrin homology (PH) domain and kinase domain, which is relieved by C-tail phosphorylation, but the precise molecular mechanisms remain elusive. Here we use a combination of protein semisynthesis, NMR, and enzymological analysis to characterize structural features of the PH domain in its autoinhibited and activated states. We find that Akt autoinhibition depends on the length/flexibility of the PH-kinase linker. We identify a role for a dynamic short segment in the PH domain that appears to regulate autoinhibition and PDK1-catalyzed phosphorylation of Thr308 in the activation loop. We determine that Akt allosteric inhibitor MK2206 drives distinct PH domain structural changes compared to baseline autoinhibited Akt. These results highlight how the conformational plasticity of Akt governs the delicate control of its catalytic properties.

Data availability

Source data: Enzyme kinetics, fluorescence binding data, western blots, SDSPAGE gels have been deposited in Dryad: http://dx.doi:10.5061/dryad.0p2ngf1xg

The following data sets were generated

Article and author information

Author details

  1. Nam Chu

    Medicine/BCMP, Harvard Medical School, Brigham and Women's Hospital, Boston, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9717-5007

  2. Thibault Viennet

    BCMP, Harvard Medical School, Dana-Farber Cancer Institute, Boston, United States
    Competing interests
    No competing interests declared.

  3. Hwan Bae

    Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5252-252X

  4. Antonieta Salguero

    Medicine/BCMP, Harvard Medical School, Brigham and Women's Hospital, Boston, United States
    Competing interests
    No competing interests declared.

  5. Andras Boeszoermenyi

    BCMP, Harvard Medical School, Dana-Farber Cancer Institute, Boston, United States
    Competing interests
    No competing interests declared.

  6. Haribabu Arthanari

    BCMP, Harvard Medical School, Dana-Farber Cancer Institute, Boston, United States
    For correspondence
    hari_arthanari@hms.harvard.edu
    Competing interests
    No competing interests declared.

  7. Philip A Cole

    Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
    For correspondence
    pacole@bwh.harvard.edu
    Competing interests
    Philip A Cole, Senior editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6873-7824

Funding

National Cancer Institute (CA74305)

  • Philip A Cole

Claudia Adams Barr Program in Innovative Cancer Research

  • Haribabu Arthanari

Austrian Science Fund (Schroedinger Fellowship)

  • Andras Boeszoermenyi

American Heart Association (19POST34380800)

  • Andras Boeszoermenyi

National Institutes of Health (EB002026)

  • Haribabu Arthanari

Kwanjeong Educational Foundation (pre-doctoral fellowship)

  • Hwan Bae

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

Copyright

© 2020, Chu 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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  1. Nam Chu
  2. Thibault Viennet
  3. Hwan Bae
  4. Antonieta Salguero
  5. Andras Boeszoermenyi
  6. Haribabu Arthanari
  7. Philip A Cole
(2020)
The Structural Determinants of PH Domain-Mediated Regulation of Akt Revealed by Segmental Labeling
eLife 9:e59151.
https://doi.org/10.7554/eLife.59151

Share this article

https://doi.org/10.7554/eLife.59151

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    1. Biochemistry and Chemical Biology
    2. Structural Biology and Molecular Biophysics

    PH domain-mediated autoinhibition and oncogenic activation of Akt

    Hwan Bae, Thibault Viennet ... Philip A Cole
    Research Advance Updated

    Akt is a Ser/Thr protein kinase that plays a central role in metabolism and cancer. Regulation of Akt’s activity involves an autoinhibitory intramolecular interaction between its pleckstrin homology (PH) domain and its kinase domain that can be relieved by C-tail phosphorylation. PH domain mutant E17K Akt is a well-established oncogene. Previously, we reported that the conformation of autoinhibited Akt may be shifted by small molecule allosteric inhibitors limiting the mechanistic insights from existing X-ray structures that have relied on such compounds (Chu et al., 2020). Here, we discover unexpectedly that a single mutation R86A Akt exhibits intensified autoinhibitory features with enhanced PH domain-kinase domain affinity. Structural and biochemical analysis uncovers the importance of a key interaction network involving Arg86, Glu17, and Tyr18 that controls Akt conformation and activity. Our studies also shed light on the molecular basis for E17K Akt activation as an oncogenic driver.