Ca(2+)-independent autophosphorylation of postsynaptic density-associated Ca2+/calmodulin-dependent protein kinase.
Neurochem Res
; 22(9): 1151-7, 1997 Sep.
Article
em En
| MEDLINE
| ID: mdl-9251106
ABSTRACT
A major protein in the postsynaptic density fraction is alpha-CAM kinase II, the alpha-subunit of the Ca2+/calmodulin-dependent protein kinase. Autophosphorylation of the postsynaptic density-associated CaM kinase II is likely to be a crucial event in the induction of activity-dependent synaptic modification. This study focuses on the regulation and consequences of Ca(2+)-independent autophosphorylation of the enzyme. In isolated postsynaptic densities, a sub-stochiometric level of autophosphorylation in the presence of Ca2+ is sufficient to trigger maximal Ca(2+)-independent autophosphorylation of alpha-CaM Kinase II. A major fraction of the sites phosphorylated in the absence of Ca2+ can be dephosphorylated by the endogenous phosphatase activity in the preparation. Ca(2+)-independent autophosphorylation is correlated with a drastic decrease in calmodulin binding to postsynaptic densities. This may represent a physiological mechanism that lower the calmodulin trapping capacity of the organelle, thus increasing the availability of calmodulin to other elements within a spine.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Sinapses
/
Cálcio
/
Proteínas Quinases Dependentes de Cálcio-Calmodulina
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
1997
Tipo de documento:
Article