Studies on the turnover and subcellular localization of membrane gangliosides in cultured neuroblastoma cells
To compare the subcellular distribution of endogenously synthesized and exogenous gangliosides, cultured murine neuroblastoma cells (N1E-115) were incubated in suspension for 22 h in the presence of D-(1-/sup 3/H)galactose or (/sup 3/H)GM1 ganglioside, transferred to culture medium containing no radioisotope for periods of up to 72 hr, and then subjected to subcellular fractionation and analysis of lipid-sialic acid and radiolabeled ganglioside levels. The results indicated that GM2 and GM3 were the principal gangliosides in the cells with only traces of GM1 and small amounts of disialogangliosides present. About 50% of the endogenously synthesized radiolabelled ganglioside in the four major subcellular membrane fractions studied was recovered from plasma membrane and only 10-15% from the crude mitochondrial membrane fraction. In contrast, 45% of the exogenous (/sup 3/H)GM1 taken up into the same subcellular membrane fractions was recovered from the crude mitochondrial fraction; less than 15% was localized in the plasma membrane fraction. The results are similar to those obtained from previously reported studies on membrane phospholipid turnover. They suggest that exogenous GM1 ganglioside, like exogenous phosphatidylcholine, does not intermix freely with any quantitatively major pool of endogenous membrane lipid.
- OSTI ID:
- 5031012
- Journal Information:
- Neurochem. Res.; (United States), Vol. 3
- Country of Publication:
- United States
- Language:
- English
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GANGLIOSIDES
TISSUE DISTRIBUTION
CELL CULTURES
CELL MEMBRANES
CULTURE MEDIA
GALACTOSE
LIPIDS
MICE
MITOCHONDRIA
SIALIC ACID
TRACER TECHNIQUES
TRITIUM COMPOUNDS
TUMOR CELLS
ALDEHYDES
ANIMAL CELLS
ANIMALS
CARBOHYDRATES
CELL CONSTITUENTS
DISTRIBUTION
HEXOSES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
MONOSACCHARIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
POLYSACCHARIDES
RODENTS
SACCHARIDES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques