Mutational scanning reveals the determinants of protein insertion and association energetics in the plasma membrane

Abstract

Insertion of helix-forming segments into the membrane and their association determines the structure, function, and expression levels of all plasma membrane proteins. However, systematic and reliable quantification of membrane-protein energetics has been challenging. We developed a deep mutational scanning method to monitor the effects of hundreds of point mutations on helix insertion and self-association within the bacterial inner membrane. The assay quantifies insertion energetics for all natural amino acids at 27 positions across the membrane, revealing that the hydrophobicity of biological membranes is significantly higher than appreciated. We further quantitate the contributions to membrane-protein insertion from positively charged residues at the cytoplasm-membrane interface and reveal large and unanticipated differences among these residues. Finally, we derive comprehensive mutational landscapes in the membrane domains of Glycophorin A and the ErbB2 oncogene, and find that insertion and self-association are strongly coupled in receptor homodimers.

Article and author information

Author details

  1. Assaf Assaf Elazar

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  2. Jonathan Weinstein

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  3. Ido Biran

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  4. Yearit Fridman

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  5. Eitan Bibi

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  6. Sarel Jacob Fleishman

    Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
    For correspondence
    sarel@weizmann.ac.il
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Yibing Shan, DE Shaw Research, United States

Publication history

  1. Received: October 6, 2015
  2. Accepted: January 28, 2016
  3. Accepted Manuscript published: January 29, 2016 (version 1)
  4. Accepted Manuscript updated: February 2, 2016 (version 2)
  5. Version of Record published: February 26, 2016 (version 3)

Copyright

© 2016, Assaf Elazar 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. Assaf Assaf Elazar
  2. Jonathan Weinstein
  3. Ido Biran
  4. Yearit Fridman
  5. Eitan Bibi
  6. Sarel Jacob Fleishman
(2016)
Mutational scanning reveals the determinants of protein insertion and association energetics in the plasma membrane
eLife 5:e12125.
https://doi.org/10.7554/eLife.12125

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