Interaction of the C-terminal region of the Ggamma protein with model membranes

Biophys J. 2007 Oct 1;93(7):2530-41. doi: 10.1529/biophysj.106.101196. Epub 2007 Jun 1.


Heterotrimeric G-proteins interact with membranes. They accumulate around membrane receptors and propagate messages to effectors localized in different cellular compartments. G-protein-lipid interactions regulate G-protein cellular localization and activity. Although we recently found that the Gbetagamma dimer drives the interaction of G-proteins with nonlamellar-prone membranes, little is known about the molecular basis of this interaction. Here, we investigated the interaction of the C-terminus of the Ggamma(2) protein (P(gamma)-FN) with model membranes and those of its peptide (P(gamma)) and farnesyl (FN) moieties alone. X-ray diffraction and differential scanning calorimetry demonstrated that P(gamma)-FN, segregated into P(gamma)-FN-poor and -rich domains in phosphatidylethanolamine (PE) and phosphatidylserine (PS) membranes. In PE membranes, FN increased the nonlamellar phase propensity. Fourier transform infrared spectroscopy experiments showed that P(gamma) and P(gamma)-FN interact with the polar and interfacial regions of PE and PS bilayers. The binding of P(gamma)-FN to model membranes is due to the FN group and positively charged amino acids near this lipid. On the other hand, membrane lipids partially altered P(gamma)-FN structure, in turn increasing the fluidity of PS membranes. These data highlight the relevance of the interaction of the C-terminal region of the Ggamma protein with the cell membrane and its effect on membrane structure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calorimetry, Differential Scanning
  • Cattle
  • Cell Membrane / metabolism
  • GTP-Binding Protein gamma Subunits / chemistry*
  • GTP-Binding Protein gamma Subunits / physiology
  • Lipids / chemistry
  • Peptides / chemistry
  • Phospholipids / chemistry
  • Protein Binding
  • Protein Structure, Tertiary
  • Spectrometry, Fluorescence
  • Spectroscopy, Fourier Transform Infrared
  • X-Ray Diffraction


  • GTP-Binding Protein gamma Subunits
  • Lipids
  • Peptides
  • Phospholipids