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Protein phosphorylation driven by intracellular calcium oscillations: a kinetic analysis
1Faculté des Sciences, Université Libre de Bruxelles, Belgium.
Biophysical Chemistry
|April 1, 1992
Summary
Cellular responses to repetitive calcium (Ca2+) spikes are influenced by protein phosphorylation. This study reveals that protein phosphorylation encodes external stimulation frequency through Ca2+ oscillations.
Area of Science:
- Cellular Biology
- Biochemistry
- Systems Biology
Background:
- Signal-induced calcium (Ca2+) oscillations are common cellular events.
- Cellular responses to these oscillations, particularly protein phosphorylation, are not fully understood.
Purpose of the Study:
- To investigate how repetitive Ca2+ spikes affect cellular responses, focusing on protein phosphorylation.
- To explore the mechanism of encoding external stimulation via Ca2+ oscillation frequency.
Main Methods:
- Numerical simulations of a theoretical model.
- Analysis of a reversible protein phosphorylation system coupled to Ca2+ oscillations (Ca2+-induced Ca2+ release).
Main Results:
- The average fraction of phosphorylated protein increases with Ca2+ spike frequency.
- Protein phosphorylation acts as a mechanism to encode external stimulation frequency.
- Efficient encoding requires specific kinetic conditions for kinase and phosphatase activity, particularly zero-order ultrasensitivity.
Conclusions:
- Protein phosphorylation can encode the frequency of signal-induced Ca2+ oscillations, thereby translating external stimuli into cellular signals.
- Precise kinetic parameters are crucial for effective frequency encoding.
- Ca2+ oscillations can drive diverse temporal patterns of protein phosphorylation.