https://staging.physiomeproject.org/w/hnielsen/dupont_erneux_1997 en-us Summary lnositol 1,4,5-trisphosphate (Ins-l ,4,5-P,) is responsible for Ca2+ mobilization in response to external stimulation in many cell types. The latter phenomenon often occurs as repetitive Ca2+ spikes. In this study, the effect of the two Ins-l ,4,5-P, metabolizing enzymes (Ins-l ,4,5-P, 3-kinase and 5-phosphatase) on the temporal pattern of Ca*+ oscillations has been investigated. On the basis of the well-documented Ins-1,4,5-P, 3-kinase stimulation by the Ca*+/calmodulin complex and of the experimentally-determined kinetic characteristics of these enzymes, we predict that 5-phosphatase primarily controls the levels of Ins-1,4,5-P,and, thereby, the occurrence and frequency of Ca*+ oscillations. Consequently, the model reproduces the experimental observation performed in Chinese hamster ovary cells that 5-phosphatase overexpression has a much more pronounced effect on the pattern of Ca*+ oscillations than 3- kinase overexpression. We also investigated, in more detail, under which conditions a similar effect could be observed in other cell types expressing various Ins-l ,4,5-P, 3-kinase activities.  https://staging.physiomeproject.org/w/hnielsen/dupont_erneux_1997/@@file/c8ed12db687ad68d36e660d0d66d60a568c6fa58 Edited HTML file Hanne Nielsen 2011-10-11 https://staging.physiomeproject.org/w/hnielsen/dupont_erneux_1997/@@file/b8c02ff182325435639c230791dd2ba6b14b834f Added updated images, session file, xul and html files Hanne Nielsen 2011-10-10 https://staging.physiomeproject.org/w/hnielsen/dupont_erneux_1997/@@file/cda081fbeb2ac9eb10aba45d9288286e215a92a8 Added updated images and the CellML file and session file Hanne Nielsen 2011-10-10 https://staging.physiomeproject.org/w/hnielsen/dupont_erneux_1997/@@file/80fb2c623270e00b8f4083ed69d10561c0132d7a Added images in ai png and svg format Hanne Nielsen 2011-10-10