https://staging.physiomeproject.org/workspace/35d en-us Cytosolic calcium plays a crucial role as a second messenger in cellular signalling. Various cell types, including hepatocytes, display Ca2+ oscillations when stimulated by an extracellular signal. However, the biological relevance of this temporal organization remains unclear. In this paper, we investigate theoretically the e!ect of Ca2+ 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 Ca2+ concentration, we show that Ca2+ 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, speciality can be encoded by the oscillation frequency. Finally, using a model for signal-induced Ca2+ oscillations based on Ca2+-induced Ca2+ release, we show that realistic Ca2+ oscillations can potentiate the response to a hormonal stimulation. These results indicate that Ca2+ oscillations in hepatocytes could contribute to increase the efficiency and speciality of cellular signalling, as shown experimentally for gene expression in lymphocytes (Dolmetsch et al., 1998). https://staging.physiomeproject.org/workspace/35d/@@file/04b1009c811755afbe54d403c23c1de090b29a98 Added SEDML files Mathieu Deneux 2016-07-28 https://staging.physiomeproject.org/workspace/35d/@@file/ee1afb6160f9a824223a8e2ea08f778a089ba525 Remove spurious carriage-return line endings... Dave Brooks 2013-01-04 https://staging.physiomeproject.org/workspace/35d/@@file/9cc2d56056c85c516e53c1d590fe34916a8b4a48 Equation 8 from original paper was wrong in model; correctly define units for all variables. dave 2013-01-04 https://staging.physiomeproject.org/workspace/35d/@@file/adae8cbbf41290ed1f54c55c5407edaae8f63fd6 Correctly define units for all variables. dave 2013-01-04 https://staging.physiomeproject.org/workspace/35d/@@file/2dfd72747a38b445cf98d2cd094d4bfd391ecc49 'Z' is no longer directly used for dPha/dt, so remove from component. dave 2013-01-04 https://staging.physiomeproject.org/workspace/35d/@@file/e47f403277d47eb2f64f295bb2bd9aa04d8182f9 Fix equations for dPha/dt and V1 to match those in original paper. dave 2013-01-04 https://staging.physiomeproject.org/workspace/35d/@@file/7a8a30141355d8fc10b1ea9a8239f67d2a5cd237 Remove initial value fro 'time' as it's an output variable. dave 2013-01-04 https://staging.physiomeproject.org/workspace/35d/@@file/cf2ba3333c2797a9dd1a35cd9316a294b7359b23 Removed error in html Hanne Nielsen 2011-11-11 https://staging.physiomeproject.org/workspace/35d/@@file/b05bfe5030de13ff9a573dfa81c40b7f386f3117 Fixed link in html file Hanne Nielsen 2011-11-11 https://staging.physiomeproject.org/workspace/35d/@@file/35a78e54dd1e751e99782c7390f77123ccda0459 Added metadata to cellML files Hanne Nielsen 2011-11-11 https://staging.physiomeproject.org/workspace/35d/@@file/c34171346c5dbd91349aa33aaba757ace1ae9a6c Added tagged images in ai svg and png format. Both models now have cliackable SVG sessions Hanne Nielsen 2011-09-12 https://staging.physiomeproject.org/workspace/35d/@@file/2a9e5102535ffde278f11f02517eeeaf45d32ab4 Added HTML file, xul and clickable session for the first cellML model. Traces still to be matched and added for second sesison file with both Pha and Z Hanne Nielsen 2011-08-23 https://staging.physiomeproject.org/workspace/35d/@@file/e461a25184f1bb0256c1f5c9829caf57575e97a9 Removed previous CellML files from workspace Hanne Nielsen 2011-08-18 https://staging.physiomeproject.org/workspace/35d/@@file/a6763c2156d8fe15df576a800053176fcd3450d8 Added new cellML files for a and b. a now reproduces results but b oscillates differently. Added session files without SVG image. To be added. Hanne Nielsen 2011-08-18 https://staging.physiomeproject.org/workspace/35d/@@file/1e4371dfbd64c0c3fb0087eb34735ab7372d1375 Added cellML files again after looking at equations. Still do not reproduce published results Hanne Nielsen 2011-08-16 https://staging.physiomeproject.org/workspace/35d/@@file/81df4382cc0a0cd3cc05a97b6dd94d87f9226895 Added images in ai svg and png format. CellML files based on equations 1-3 (a) and 4-8 (b). HTML file also added. Does not reproduce published figure ut does run in OpenCell. Hanne Nielsen 2011-08-08 https://staging.physiomeproject.org/workspace/35d/@@file/37d1087504895fcf2a34ac4d747d6aa57a161aad Added images and HTML file to workspace Hanne Nielsen 2011-08-08