Energized endocytosis in human erythrocyte ghosts.
J Clin Invest
; 56(1): 8-22, 1975 Jul.
Article
em En
| MEDLINE
| ID: mdl-124748
ABSTRACT
The mechanism of endocytosis in resealed human erythrocyte ghosts was studied. The energy for endocytosis or micropinocytosis appears to be derived from Mg-ATP, and membrane internalization is preceded by activation of a membrane-associated Ca,Mg-ATPase and by the active efflux of Ca. Endocytosis, Ca,Mg-ATPase activity, and active Ca efflux all require the presence of Mg. Furthermore, these three phenomena, endocytosis, Ca,Mg-ATPase activity, and active Ca extrusion, all have a concentration dependence on Ca such that low concentrations stimulate and higher concentrations inhibit the phenomena. The optimal concentration of Ca is identical for endocytosis, active Ca efflux, and Ca,Mg-ATPase. Morphologic studies indicated that while active Ca efflux and activation of the Ca,Mg-ATPase activity occurred promptly upon onset of incubation, there was a significant time delay before endocytosis occurred, which suggests that endocytosis additionally involved a more slowly functioning mechanicochemical mechanism. Ruthenium red, a specific inhibitor of Ca,Mg-ATPase and Ca transport, inhibited endocytosis in a concentration-related manner. Prostaglandins E1 and E2 had no measurable effect on ghost endocytosis, active Ca efflux, or Ca,Mg-ATPase activity.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fagocitose
/
Endocitose
/
Eritrócitos
Limite:
Humans
Idioma:
En
Ano de publicação:
1975
Tipo de documento:
Article