Interaction of the C-terminal region of the Ggamma protein with model membranes.
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.
Barceló
Francisca
F
Laboratory of Molecular and Cellular Biomedicine, Associate Unit of the Instituto de la Grasa (Consejo Superior de Investigaciones Científicas), University of the Balearic Islands, E-07122 Palma de Mallorca, Spain. francisca.barcelo@uib.es
Prades
Jesús
J
Encinar
José Antonio
JA
Funari
Sérgio S
SS
Vögler
Oliver
O
González-Ros
José Manuel
JM
Escribá
Pablo V
PV
D000818:Animals; D002152:Calorimetry, Differential Scanning; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D044388:GTP-Binding Protein gamma Subunits / Q000737:chemistry* / Q000502:physiology; D008055:Lipids / Q000737:chemistry; D010455:Peptides / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013050:Spectrometry, Fluorescence; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
D044388:GTP-Binding Protein gamma Subunits; D008055:Lipids; D010455:Peptides; D010743:Phospholipids