Location: Activation of the Liver Glycogen Phosphorylase by Ca2+ Oscillations: a Theoretical Study @ 9cc2d56056c8 / gall_2000.cellml

Author:

dave <dave@bcs.co.nz>

Date:

2013-01-04 12:32:48+13:00

Desc:

Equation 8 from original paper was wrong in model; correctly define units for all variables.

Permanent Source URI:

https://models.physiomeproject.org/workspace/35d/rawfile/9cc2d56056c85c516e53c1d590fe34916a8b4a48/gall_2000.cellml

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This CellML file was generated on 8/18/2011 at 1:13:53 at PM using:





COR (0.9.31.1409)


Copyright 2002-2011 Dr Alan Garny


http://cor.physiol.ox.ac.uk/ - cor@physiol.ox.ac.uk





CellML 1.0 was used to generate this model


http://www.cellml.org/


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         Made in COR. Model a runs in OpenCell to recreate results from  published paper but model b does not reproduce results. CellML files are based on equations 1-3 (a) and 1 and 4-8 (b).


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ABSTRACT: Cytosolic calcium plays a crucial role as a second messenger in cellular signalling. Various cell types, including hepatocytes, display Ca(2+)oscillations when stimulated by an extracellular signal. However, the biological relevance of this temporal organization remains unclear. In this paper, we investigate theoretically the effect of Ca(2+)oscillations on a particular example of cell regulation: the phosphorylation-dephosphorylation cycle controlling the activation of glycogen phosphorylase in hepatocytes. By modelling periodic sinusoidal variations in the intracellular Ca(2+)concentration, we show that Ca(2+)oscillations reduce the threshold for the activation of the enzyme. Furthermore, as the activation of a given enzyme depends on the kinetics of its phosphorylation-dephosphorylation cycle, specificity can be encoded by the oscillation frequency. Finally, using a model for signal-induced Ca(2+)oscillations based on Ca(2+)-induced Ca(2+)release, we show that realistic Ca(2+)oscillations can potentiate the response to a hormonal stimulation. These results indicate that Ca(2+)oscillations in hepatocytes could contribute to increase the efficiency and specificity of cellular signalling, as shown experimentally for gene expression in lymphocytes (Dolmetsch et al., 1998).</para>





        <para>


The complete original paper reference is cited below:


</para>


        <para>


         Activation of the Liver Glycogen Phosphorylase by Ca2+ Oscillations: a Theoretical Study, David Gall et al, 2009, <emphasis>Activation of the Liver Glycogen Phosphorylase by Ca2+ Oscillations: 


a Theoretical Study </emphasis>, 207, 445-454. <ulink url="http://www.ncbi.nlm.nih.gov/pubmed/11093832">PubMed ID: 11093832</ulink>


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           Activation of the liver glycogen phosphorylase by Ca(2+)oscillations: a theoretical study


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