Atomic force microscopy studies of ganglioside GM1alpha in dioleoylphosphatidylcholine/dipalmitoylphosphatidylcholine mixed monolayers and hybrid bilayers.
The membrane states of the alpha-series ganglioside GM1alpha in 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) mixed monolayers and hybrid bilayers were investigated using atomic force microscopy (AFM). The AFM image for the GM1alpha/DOPC/DPPC ternary monolayers showed the formation of GM1alpha-raft in the DOPC matrix. As increase of the surface pressure, GM1alpha are condensed in DPPC-rich domains; long and slender GM1alpha-rafts are separated from the DPPC-rich domains into the DOPC matrix. The GM1alpha/DOPC/DPPC ternary monolayers were deposited on mica coated with the first layer (1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine: DPPE) using the Langmuir-Schaeffer technique. The AFM image for the hybrid bilayers showed that same molecules were heterogeneously concentrated according to increase of the surface pressure to form GM1alpha-raft, DPPC-rich domain and DOPC matrix, being in agreement with the observation on the monolayer experiment. The found phenomenon implies that a binding of lectin to GM1alpha causes the increase of the surface pressure, the localization of GM1alpha and the succeeding formation of the raft as a first step of a specific signal transduction.
Takeda
Yoichi
Y
Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
Horito
Shigeomi
S
D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry*; D005677:G(M1) Ganglioside / Q000737:chemistry*; D005732:Gangliosides / Q000737:chemistry*; D008051:Lipid Bilayers; D018625:Microscopy, Atomic Force / Q000379:methods; D008968:Molecular Conformation; D010713:Phosphatidylcholines / Q000737:chemistry*; D011312:Pressure; D013499:Surface Properties
D005732:Gangliosides; D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D005677:G(M1) Ganglioside; C017251:1,2-oleoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine