Effect of sphingosine on domain morphology in giant vesicles.
Sphingosine is a bioactive molecule which is known to participate in the regulation of a number of cellular processes such as apoptosis, cell differentiation, growth, etc. Sphingosine was observed to exhibit different domain morphology depending on the surrounding lipid matrix in biomimetic systems such as giant vesicles. Our current results showed that in a glycerophospholipid matrix sphingosine segregated in gel leaf-like domains whereas cholesterol presence increased its miscibility by melting gel domains in a concentration-dependent manner. Sphingosine and cholesterol did not form merging liquid domains on the micron scale as observed for sphingomyelin and cholesterol. However, we were able to visualize that sphingosine appears as a stabilizer and amplifier of domains in liquid-ordered phase by increasing the temperature of their formation and fraction. These results imply that sphingosine acts as a modulator of the lipid domain formation and thus it could exert its biological role, not only through direct binding to proteins, but also indirectly by influencing their sorting in membranes and modulating the processes of signal transduction.
Georgieva
Raina
R
Institute of Biophysics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl, 21, 1113 Sofia, Bulgaria.
Koumanov
Kamen
K
Momchilova
Albena
A
Tessier
Cedric
C
Staneva
Galya
G
D000818:Animals; D002417:Cattle; D002645:Chickens; D022162:Cytoplasmic Vesicles / Q000737:chemistry*; D004530:Egg Yolk / Q000737:chemistry; D021962:Membrane Microdomains / Q000737:chemistry*; D013110:Sphingosine / Q000737:chemistry / Q000378:metabolism*
D013110:Sphingosine