Artículos de revistas
StarD7 behaves as a fusogenic protein in model and cell membrane bilayers
Fecha
2012-03-03Registro en:
Angeletti, Sofia Claudia; Sanchez, Julieta Maria; Chamley, Larry W.; Genti de Raimondi, Susana; Perillo, Maria Angelica; StarD7 behaves as a fusogenic protein in model and cell membrane bilayers; Elsevier Science; Biochimica et Biophysica Acta - Biomembranes; 1818; 3; 3-3-2012; 425-433
0005-2736
CONICET Digital
CONICET
Autor
Angeletti, Sofia Claudia
Sanchez, Julieta Maria
Chamley, Larry W.
Genti de Raimondi, Susana
Perillo, Maria Angelica
Resumen
StarD7 is a surface active protein, structurally related with the START lipid transport family. So, the present work was aimed at elucidating a potential mechanism of action for StarD7 that could be related to its interaction with a lipid–membrane interface. We applied an assay based on the fluorescence de-quenching of BD-HPC-labeled DMPC–DMPS 4:1 mol/mol SUVs (donor liposomes) induced by the dilution with non-labeled DMPC–DMPS 4:1 mol/mol LUVs (acceptor liposomes). Recombinant StarD7 accelerated the dilution of BD-HPC in a concentration-dependent manner. This result could have been explained by either a bilayer fusion or monomeric transport of the labeled lipid between donor and acceptor liposomes. Further experiments (fluorescence energy transfer between DPH-HPC/BD-HPC, liposome size distribution analysis by dynamic light scattering, and the multinuclear giant cell formation induced by recombinant StarD7) strongly indicated that bilayer fusion was the mechanism responsible for the StarD7-induced lipid dilution. The efficiency of lipid dilution was dependent on StarD7 electrostatic interactions with the lipid–water interface, as shown by the pH- and salt-induced modulation. Moreover, this process was favored by phosphatidylethanolamine which is known to stabilize non-lamellar phases considered as intermediary in the fusion process. Altogether these findings allow postulate StarD7 as a fusogenic protein.