Interaction of KRas4b with anionic membranes: A special role for PIP2

Michael C. Gregory, Mark A. McLean, Stephen G. Sligar

Research output: Contribution to journalArticle

Abstract

KRas4b is a small G-protein whose constitutively active oncogenic mutants are present in 90% of pancreatic cancers. Using fully post-translationally modified KRAS4b, we investigated the role of lipid identity in the recruitment of KRas4b to a membrane surface of defined composition. Application of a newly developed single frequency fluorescence anisotropy decay experiment to this system revealed that KRas4b has a significant binding preference for Nanodisc bilayers containing PIP2. We conducted molecular dynamics simulations to look for an origin of this specificity. In the case of membranes containing PIP2 the protein formed long-lived salt bridges with PIP2 head groups but not the monovalent DMPS, explaining the experimentally observed lipid specificity. Additionally, we report that PIP2 forms key contacts with Helix-4 on the catalytic domain of KRas4b that orient the protein in a manner expected to facilitate association with upstream and downstream signaling partners.

Original languageEnglish (US)
Pages (from-to)351-355
Number of pages5
JournalBiochemical and Biophysical Research Communications
Volume487
Issue number2
DOIs
StatePublished - May 27 2017

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Unithiol
Membranes
Lipids
Fluorescence Polarization
Monomeric GTP-Binding Proteins
Molecular Dynamics Simulation
Pancreatic Neoplasms
Molecular dynamics
Catalytic Domain
Proteins
Anisotropy
Salts
Fluorescence
Head
Association reactions
Computer simulation
Chemical analysis
Experiments

Keywords

  • Cancer signaling
  • KRas4b
  • Lipid specificity
  • Nanodisc
  • PIP

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Interaction of KRas4b with anionic membranes : A special role for PIP2. / Gregory, Michael C.; McLean, Mark A.; Sligar, Stephen G.

In: Biochemical and Biophysical Research Communications, Vol. 487, No. 2, 27.05.2017, p. 351-355.

Research output: Contribution to journalArticle

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