The effect of castanospermine on the synthesis of synaptic glycoproteins by rat brain slices.
Neurochem Res
; 15(3): 257-63, 1990 Mar.
Article
em En
| MEDLINE
| ID: mdl-2195374
ABSTRACT
Slices were prepared from rat forebrains and the incorporation of [3H]mannose and [35S]methionine into proteins and glycoproteins determined. The incorporation of methionine continued to increase for up to 8 hours whereas mannose incorporation was maximal between 2 and 4 hours and declined thereafter. Glycopeptides prepared by pronase digestion of [3H]mannose-labeled glycoproteins were digested with endoglucosaminidase H (endo H) and analysed by gel filtration. The major endo H-sensitive oligosaccharide eluted in a position similar to standard Man8GlcNAc. In the presence of castanospermine, which inhibits glucosidase I, the first enzymatic step in the processing of N-linked oligosaccharides, a new endo H-sensitive glycan similar in size to standard Glc3Man9GlcNAc2 accumulated. Synaptic membranes (SMs) were isolated from slices which had been incubated with either [3H]mannose or [35S]methionine in the presence and absence of castanospermine. In the presence of inhibitor the relative incorporation of [3H]mannose into high-mannose glycans of synaptic glycoproteins was increased. The incorporation of newly synthesized, [35S] methionine-labeled, Con A-binding glycoproteins into SMs was not affected by the addition of inhibitor. Many of the glycoproteins synthesized in the presence of castanospermine exhibited a decreased electrophoretic mobility indicative of the presence of altered oligosaccharide chains. The results indicate that changes in oligosaccharide composition produced by castanospermine had little effect on the subsequent transport and incorporation of glycoproteins into synaptic membranes.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Membranas Sinápticas
/
Encéfalo
/
Glicoproteínas
/
Alcaloides
/
Indolizinas
/
Proteínas do Tecido Nervoso
Limite:
Animals
Idioma:
En
Revista:
Neurochem Res
Ano de publicação:
1990
Tipo de documento:
Article
País de afiliação:
Canadá