Luciani P, Berti D, Fortini M, Baglioni P, Ghelardini C, Pacini A, Manetti D, Gualtieri F, Bartolini A, Di Cesare Mannelli L. Receptor-independent modulation of reconstituted Galpha(i) protein mediated by liposomes.
MOLECULAR BIOSYSTEMS 2009;
5:356-67. [PMID:
19396372 DOI:
10.1039/b815042g]
[Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A cationic amphiphile, BC5 (N-pentadecylpiperidin-4-amine), was recently designed and tested for its ability to directly stimulate the activity of recombinant Galpha inhibitory subunits. However, amphiphilic drugs can self-associate and bind to plasma membranes, causing undesired side effects. In this contribution, we report on the incorporation of BC5 in 1,2-dipalmytoyl-sn-glycerophosphocoline (DPPC) liposomes and on the characterization of the mixed DPPC/BC5 systems at various lipid/drug mole ratios by means of dynamic light scattering, differential scanning calorimetry and fluorescence spectroscopy. The myristoylated Galpha(i) subunit (Galpha-mir) was reconstituted in 1,2-dimiristoyl-sn-glycerophosphocoline (DMPC) bilayers, as a mimic of the drug target. We compare several reconstitution procedures in liposomes and present for the first time a complete characterization of a Galpha subunit reconstitution in model membranes in terms of protein activity as a function of the reconstitution protocol. The incorporation of the drug in DPPC bilayers resulted in enhanced Gi-modulating efficiency (evaluated in terms of binding to GTPgammaS (guanosine-5'-(gamma-thio)-triphosphate)). A correlation of the physico-chemical features and binding activity of protein-containing membrane model is proposed.
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