Protein kinase-dependent phosphorylation of cardiac sarcolemmal Ca2(+)-ATPase, as studied with a specific monoclonal antibody.
J Biochem
; 108(2): 222-9, 1990 Aug.
Article
en En
| MEDLINE
| ID: mdl-2146259
ABSTRACT
Phosphorylation of the Ca2(+)-pump ATPase of cardiac sarcolemmal vesicles by exogenously added protein kinases was examined to elucidate the molecular basis for its regulation. The Ca2(+)-pump ATPase was isolated from protein kinase-treated sarcolemmal vesicles using a monoclonal antibody raised against the erythrocyte Ca2(+)-ATPase. Protein kinase C (C-kinase) was found to phosphorylate the Ca2(+)-ATPase. The stoichiometry of this phosphorylation was about 1 mol per mol of the ATPase molecule. The C-kinase activation resulted in up to twofold acceleration of Ca2+ uptake by sarcolemmal vesicles due to its effect on the affinity of the Ca2+ pump for Ca2+ in both the presence and absence of calmodulin. Both the phosphorylation and stimulation of ATPase activity by C kinase were also observed with a highly-purified Ca2(+)-ATPase preparation isolated from cardiac sarcolemma with calmodulin-Sepharose and a high salt-washing procedure. Thus, C-kinase appears to stimulate the activity of the sarcolemmal Ca2(+)-pump through its direct phosphorylation. In contrast to these results, neither cAMP-dependent protein kinase, cGMP-dependent protein kinase nor Ca2+/calmodulin-dependent protein kinase II phosphorylated the Ca2(+)-ATPase in the sarcolemmal membrane or the purified enzyme preparation, and also they exerted virtually no effect on Ca2+ uptake by sarcolemmal vesicles.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Proteínas Quinasas
/
Sarcolema
/
ATPasas Transportadoras de Calcio
/
Miocardio
Límite:
Animals
/
Humans
Idioma:
En
Revista:
J Biochem
Año:
1990
Tipo del documento:
Article