Phosphorylation of brain synaptic and coated vesicle proteins by endogenous Ca2+/calmodulin- and cAMP-dependent protein kinases.
J Neurochem
; 40(3): 711-8, 1983 Mar.
Article
em En
| MEDLINE
| ID: mdl-6298368
ABSTRACT
Phosphorylation of brain synaptic and coated vesicle proteins was stimulated by Ca2+ and calmodulin. As determined by 5-15% sodium dodecylsulfate (SDS) polyacrylamide gel electrophoresis (PAGE), molecular weights (Mr) of the major phosphorylated proteins were 55,000 and 53,000 in synaptic vesicles and 175,000 and 55,000 in coated vesicles. In synaptic vesicles, phosphorylation was inhibited by affinity-purified antibodies raised against a 30,000 Mr protein doublet endogenous to synaptic and coated vesicles. When this doublet, along with clathrin, was extracted from coated vesicles, phosphorylation did not take place, implying that the protein doublet may be closely associated with Ca2+/calmodulin-dependent protein kinase. Affinity-purified antibodies, raised against clathrin used as a control antibody, failed to inhibit Ca2+/calmodulin-dependent phosphorylation in either synaptic or coated vesicles. Immunoelectron cytochemistry revealed that this protein doublet was present in axon terminal synaptic and coated vesicles. Synaptic vesicles also displayed cAMP-dependent kinase activity; coated vesicles did not. The molecular weights of phosphorylated synaptic vesicle proteins in the presence of Mg2+ and cAMP were 175,000, 100,000, 80,000, 57,000, 55,000, 53,000, 40,000, and 30,000. Based on the different phosphorylation patterns observed in synaptic and coated vesicles, we propose that brain vesicle protein kinase activities may be involved in the regulation of exocytosis and in retrieval of synaptic membrane in presynaptic axon terminals.
Buscar no Google
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas Quinases
/
Encéfalo
/
Proteínas de Ligação ao Cálcio
/
Calmodulina
/
Cálcio
/
AMP Cíclico
Limite:
Animals
Idioma:
En
Revista:
J Neurochem
Ano de publicação:
1983
Tipo de documento:
Article