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Calmodulin-binding peptide PEP-19 modulates activation of calmodulin kinase II In situ
R A Johanson1, H M Sarau, J J Foley
1Department of Protein Biochemistry, SmithKline Beecham Research and Development, King of Prussia, Pennsylvania 19406, USA.
Summary
PEP-19 peptide regulates calmodulin kinase II (CaM kinase II) activation in neurons. Its presence alters CaM kinase II response to stimuli, suggesting a role in modulating neuronal activity rather than global suppression.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- PEP-19 is a neuronal polypeptide associated with degeneration resistance.
- PEP-19 binds apo-calmodulin and inhibits calmodulin-dependent enzymes in vitro.
- Regulation of calmodulin-dependent enzymes by PEP-19 in intact cells remains uncharacterized.
Purpose of the Study:
- To investigate PEP-19's effect on calmodulin kinase II (CaM kinase II) activation in intact cells.
- To determine if PEP-19 regulates CaM kinase II activation in response to different stimuli.
- To elucidate the mechanism by which PEP-19 modulates CaM kinase II activity.
Main Methods:
- Transfection of PC12 cells to express physiological levels of PEP-19.
- Stimulation of CaM kinase II activation via high K+ depolarization and ATP-induced calcium influx.
- Measurement of CaM kinase II activation and assessment of calmodulin expression and calcium permeability.
Main Results:
- PEP-19 expression prevented CaM kinase II activation upon high K+ depolarization.
- CaM kinase II could still be fully activated by ATP-induced calcium influx in PEP-19 expressing cells.
- PEP-19's effects were not due to changes in calmodulin levels or cellular calcium permeability.
Conclusions:
- PEP-19 regulates CaM kinase II activation in situ in a stimulus-dependent manner.
- PEP-19 selectively modulates access to calmodulin activity, rather than globally suppressing it.
- PEP-19 may play a role in fine-tuning neuronal responses to specific stimuli.