1. Structural Biology and Molecular Biophysics

The acidic domain of the endothelial membrane protein GPIHBP1 stabilizes lipoprotein lipase activity by preventing unfolding of its catalytic domain

  1. Simon Mysling
  2. Kristian Kølby Kristensen
  3. Mikael Larsson
  4. Anne P Beigneux
  5. Henrik Gårdsvoll
  6. Fong G Loren
  7. André Bensadouen
  8. Thomas JD Jørgensen
  9. Stephen G Young
  10. Michael Ploug  Is a corresponding author
  1. Rigshospitalet, Denmark
  2. University of California, Los Angeles, United States
  3. Rigshospitalet, United States
  4. Cornell University, United States
  5. University of Southern Denmark, Denmark
https://doi.org/10.7554/eLife.12095
Share this article
Cite this article
  1. Simon Mysling
  2. Kristian Kølby Kristensen
  3. Mikael Larsson
  4. Anne P Beigneux
  5. Henrik Gårdsvoll
  6. Fong G Loren
  7. André Bensadouen
  8. Thomas JD Jørgensen
  9. Stephen G Young
  10. Michael Ploug
(2016)
The acidic domain of the endothelial membrane protein GPIHBP1 stabilizes lipoprotein lipase activity by preventing unfolding of its catalytic domain
eLife 5:e12095.
https://doi.org/10.7554/eLife.12095
  2. Download BibTeX
  3. Download .RIS

Abstract

GPIHBP1 is a glycolipid-anchored membrane protein of capillary endothelial cells that binds lipoprotein lipase (LPL) within the interstitial space and shuttles it to the capillary lumen. The LPL•GPIHBP1 complex is responsible for margination of triglyceride-rich lipoproteins along capillaries and their lipolytic processing. The current work conceptualizes a model for the GPIHBP1•LPL interaction based on biophysical measurements with hydrogen-deuterium exchange/mass spectrometry, surface plasmon resonance, and zero-length cross-linking. According to this model, GPIHBP1 is comprised of two functionally distinct domains: (1) an intrinsically disordered acidic N-terminal domain; and (2) a folded C-terminal domain that tethers GPIHBP1 to the cell membrane by glycosylphosphatidylinositol. We demonstrate that these domains serve different roles in regulating the kinetics of LPL binding. Importantly, the acidic domain stabilizes LPL catalytic activity by mitigating the global unfolding of LPL's catalytic domain. This study provides a conceptual framework for understanding intravascular lipolysis and GPIHBP1 and LPL mutations causing familial chylomicronemia.

Article and author information

Author details

  1. Simon Mysling

    Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark
    Competing interests
    No competing interests declared.

  2. Kristian Kølby Kristensen

    Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark
    Competing interests
    No competing interests declared.

  3. Mikael Larsson

    Department of Medicine, University of California, Los Angeles, Los Angeles, United States
    Competing interests
    No competing interests declared.

  4. Anne P Beigneux

    Department of Medicine, University of California, Los Angeles, Los Angeles, United States
    Competing interests
    No competing interests declared.

  5. Henrik Gårdsvoll

    Finsen Laboratory, Rigshospitalet, Copenhagen, United States
    Competing interests
    No competing interests declared.

  6. Fong G Loren

    Department of Medicine, University of California, Los Angeles, Loa Angeles, United States
    Competing interests
    No competing interests declared.

  7. André Bensadouen

    Division of Nutritional Science, Cornell University, Ithaca, United States
    Competing interests
    No competing interests declared.

  8. Thomas JD Jørgensen

    Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
    Competing interests
    No competing interests declared.

  9. Stephen G Young

    Department of Medicine, University of California, Los Angeles, Los Angeles, United States
    Competing interests
    Stephen G Young, Reviewing editor, eLife.

  10. Michael Ploug

    Finsen Laboratory, Rigshospitalet, Copenhagen, Denmark
    For correspondence
    m-ploug@finsenlab.dk
    Competing interests
    No competing interests declared.

Reviewing Editor

  1. Christopher K. Glass, University of California, San Diego, United States

Version history

  1. Received: October 5, 2015
  2. Accepted: January 2, 2016
  3. Accepted Manuscript published: January 3, 2016 (version 1)
  4. Version of Record published: February 3, 2016 (version 2)
  5. Version of Record updated: May 9, 2016 (version 3)

Copyright

© 2016, Mysling 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

  • 2,196
    views
  • 544
    downloads
  • 62
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

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)

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

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

  1. Simon Mysling
  2. Kristian Kølby Kristensen
  3. Mikael Larsson
  4. Anne P Beigneux
  5. Henrik Gårdsvoll
  6. Fong G Loren
  7. André Bensadouen
  8. Thomas JD Jørgensen
  9. Stephen G Young
  10. Michael Ploug
(2016)
The acidic domain of the endothelial membrane protein GPIHBP1 stabilizes lipoprotein lipase activity by preventing unfolding of its catalytic domain
eLife 5:e12095.
https://doi.org/10.7554/eLife.12095

Share this article

https://doi.org/10.7554/eLife.12095

Categories and tags

Research organism

Further reading

    1. Structural Biology and Molecular Biophysics

    The angiopoietin-like protein ANGPTL4 catalyzes unfolding of the hydrolase domain in lipoprotein lipase and the endothelial membrane protein GPIHBP1 counteracts this unfolding

    Simon Mysling, Kristian Kølby Kristensen ... Michael Ploug
    Research Advance

    Lipoprotein lipase (LPL) undergoes spontaneous inactivation via global unfolding and this unfolding is prevented by GPIHBP1 (Mysling et al., 2016). We now show: (1) that ANGPTL4 inactivates LPL by catalyzing the unfolding of its hydrolase domain; (2) that binding to GPIHBP1 renders LPL largely refractory to this inhibition; and (3) that both the LU domain and the intrinsically disordered acidic domain of GPIHBP1 are required for this protective effect. Genetic studies have found that a common polymorphic variant in ANGPTL4 results in lower plasma triglyceride levels. We now report: (1) that this ANGPTL4 variant is less efficient in catalyzing the unfolding of LPL; and (2) that its Glu-to-Lys substitution destabilizes its N-terminal α-helix. Our work elucidates the molecular basis for regulation of LPL activity by ANGPTL4, highlights the physiological relevance of the inherent instability of LPL, and sheds light on the molecular defects in a clinically relevant variant of ANGPTL4.

    1. Structural Biology and Molecular Biophysics

    Plasticity of the proteasome-targeting signal Fat10 enhances substrate degradation

    Hitendra Negi, Aravind Ravichandran ... Ranabir Das
    Research Article

    The proteasome controls levels of most cellular proteins, and its activity is regulated under stress, quiescence, and inflammation. However, factors determining the proteasomal degradation rate remain poorly understood. Proteasome substrates are conjugated with small proteins (tags) like ubiquitin and Fat10 to target them to the proteasome. It is unclear if the structural plasticity of proteasome-targeting tags can influence substrate degradation. Fat10 is upregulated during inflammation, and its substrates undergo rapid proteasomal degradation. We report that the degradation rate of Fat10 substrates critically depends on the structural plasticity of Fat10. While the ubiquitin tag is recycled at the proteasome, Fat10 is degraded with the substrate. Our results suggest significantly lower thermodynamic stability and faster mechanical unfolding in Fat10 compared to ubiquitin. Long-range salt bridges are absent in the Fat10 structure, creating a plastic protein with partially unstructured regions suitable for proteasome engagement. Fat10 plasticity destabilizes substrates significantly and creates partially unstructured regions in the substrate to enhance degradation. NMR-relaxation-derived order parameters and temperature dependence of chemical shifts identify the Fat10-induced partially unstructured regions in the substrate, which correlated excellently to Fat10-substrate contacts, suggesting that the tag-substrate collision destabilizes the substrate. These results highlight a strong dependence of proteasomal degradation on the structural plasticity and thermodynamic properties of the proteasome-targeting tags.

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

    Special Issue: Allosteric regulation of kinase activity

    Amy H Andreotti, Volker Dötsch
    Editorial

    The articles in this special issue highlight how modern cellular, biochemical, biophysical and computational techniques are allowing deeper and more detailed studies of allosteric kinase regulation.