Effects of monensin on glycosphingolipid metabolism in cultured human proximal tubular cells.
Indian J Biochem Biophys
;
1993 Dec; 30(6): 346-52
Artigo
em Inglês
| IMSEAR
| ID: sea-28765
ABSTRACT
Effects of monensin, a monovalent cationic ionophore which disrupts Golgi apparatus and its related functions, on glycosphingolipid (GSL) metabolism were investigated in cultured human proximal tubular (PT) cells. Monensin (10(-6) M) stimulated [3H]Gal incorporation into GlcCer, GalCer and LacCer by 8.5-fold and 15-fold, respectively, in PT cells as compared to control. In contrast, [3H]Gal incorporation into GbOse3Cer and GM3 remained unchanged and that into GbOse4Cer was decreased 2-fold as compared to control. GSL measured by HPLC revealed that in cells incubated with monensin, GlcCer, GalCer and LacCer levels were increased 1.6-fold and 7-fold, respectively, whereas GbOse3Cer and GbOse4Cer levels were decreased several folds. Cells incubated with monensin contained 2.5- to 3-fold higher activity of alpha-galactosidase, beta-galactosidase and beta-glucosidase than control, whereas the activity of UDP-gal glucosylceramide galactosyltransferase (beta-GalT-2) was 8-fold lower than control cells. Cells incubated with monensin took up and degraded one-half as much 125I-LDL as that of control cells. In control cells, exogenously derived [3H]LacCer on LDL was rapidly taken up and catabolized to monoglycosylceramide, or it was used for the endogenous synthesis of globotriosylceramide (trihexosylceramide), globotetraosylceramide (tetrahexosylceramide) and a ganglioside, GM3. In contrast, cells incubated with monensin accumulated most of the [3H]LacCer-LDL. Exogenously derived [3H]LacCer on LDL was catabolized to GlcCer, but was not utilized, for the synthesis of globotriosylceramide, globotetraosylceramide and GM3 in cells incubated with monensin.(ABSTRACT TRUNCATED AT 250 WORDS)
Texto completo:
DisponíveL
Índice:
IMSEAR (Sudeste Asiático)
Assunto principal:
Humanos
/
Glicoesfingolipídeos
/
Monensin
/
Linhagem Celular
/
Células Cultivadas
/
Beta-Galactosidase
/
Beta-Glucosidase
/
Fibroblastos
/
Galactose
/
Galactosiltransferases
Idioma:
Inglês
Revista:
Indian J Biochem Biophys
Ano de publicação:
1993
Tipo de documento:
Artigo
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