Defining erythrocyte internal labeling by phosphorylation.
Proc Natl Acad Sci U S A
; 81(9): 2767-71, 1984 May.
Article
en En
| MEDLINE
| ID: mdl-6585827
When erythrocytes are incubated with 32Pi, incorporation of label into phosphoproteins is a gradual process, increasing for at least 2 hours. Membrane phospholipids also are labeled. Exogenous protein kinase substrates are unlabeled in these incubations. This suggests that labeling by 32Pi occurs into polypeptides inside the erythrocytes. When erythrocytes are incubated with [gamma-32P]ATP and active protein kinase, membrane polypeptides are not labeled. Only exogenously added protein kinase substrates and the regulatory subunit of protein kinase (and its contaminants) are labeled. This suggests that labeling from [gamma-32P]ATP and active protein kinase occurs in the compartment outside the erythrocytes. Apyrase (EC 3.6.1.5) eliminates such labeling, demonstrating that it was occurring in the compartment external to the erythrocytes. However, in incubations of cells with 32Pi, apyrase has no effect on the incorporation into membrane polypeptides and phospholipids, demonstrating that this labeling occurs on the inside of the membrane. Thus, additions of apyrase to intact particles incubated with protein kinase substrates and 32Pi provides a method for identifying internally exposed polypeptides in the plasma membranes of a variety of systems.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Membrana Eritrocítica
/
Proteínas de la Membrana
Límite:
Humans
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Año:
1984
Tipo del documento:
Article
Pais de publicación:
Estados Unidos