Autophosphorylation of type II Ca2+/calmodulin-dependent protein kinase in cultures of postnatal rat hippocampal slices
| Autor: | Sean S. Molloy, Mary B. Kennedy |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Phosphopeptides
Aging Calmodulin Biology Hippocampus Piperazines chemistry.chemical_compound Organ Culture Techniques 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine Ca2+/calmodulin-dependent protein kinase Animals Phosphorylation Kinase activity Protein kinase A Egtazic Acid Multidisciplinary Kinase Autophosphorylation Brain Rats Inbred Strains Okadaic acid Isoquinolines Molecular biology Rats Kinetics chemistry Organ Specificity Calcium-Calmodulin-Dependent Protein Kinases biology.protein Calcium Protein Kinases Research Article |
| Zdroj: | Proceedings of the National Academy of Sciences. 88:4756-4760 |
| ISSN: | 1091-6490 0027-8424 |
| Popis: | Autophosphorylation of Thr^(286) on type II Ca^(2+)/calmodulin-dependent protein kinase (CaM kinase) in vitro causes kinase activity to become partially independent of Ca^(2+). Here we report that Thr^(286) is the major CaM kinase autophosphorylation site occupied in situ in "organotypic" hippocampal cultures. Measurement of Ca^(2+)-independent CaM kinase activity revealed that approximately one-third of the kinase is autophosphorylated in situ when the basal Ca^(2+) concentration is 15-43 nM. This proportion was substantially reduced 30 min after removal of extracellular Ca^(2+) or treatment of the cultures with protein kinase inhibitors and was increased by treatment with okadaic acid. Therefore, the high proportion of autophosphorylated kinase at basal Ca^(2+) concentrations appears to be maintained by Ca^(2+)-dependent autophosphorylation. Homogenates of intact hippocampi also contain a high proportion of Ca^(2+)-independent type II CaM kinase, 13-23% depending on developmental age. Thus, in hippocampal neurons, an important function of the autophosphorylation mechanism may be to produce a relatively high level of CaM kinase activity, even at basal Ca^(2+) concentrations, permitting both upward and downward local regulation by physiological agents. |
| Databáze: | OpenAIRE |
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