Making Sense of Complexity Summary of the Workshop on Dynamical Modeling of Complex Biomedical Systems (2002) / Chapter Skim
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2 Modeling Processes within the Cell
2 Modeling Processes within the Cell
Pages 4-9
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From page 4... ...
Workshop speaker James Weiss, of the University of California at Los Angeles, outlined a strategy for going in that direction by first considering a simple model that might relate the simple gene to the complex organism. His strategy begins by asking what the most generic features of a particular physiological process are and then goes on to build a simple model that could, in principle, relate the genomic input to those features.
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From page 5... ...
Using the basic premise that cardiac tissue is an excitable medium, Weiss proposed a wave model. In his model, fibrillation is the result of a breaking wave, and the onset of fibrillation occurs when the wave first breaks; it escalates into full fibrillation as the wave oscillation increases.
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From page 6... ...
, and one obvious approach to modeling this network would view it as consisting of three parts: Cues ~ Intracellular signals ~ Cell function Douglas Lauffenburger of MIT adopted this approach to model the quantitative dynamics of the ERK2 signal as it responds to an external cue (fibronectin, a protein involved in many important cellular processes) and helps lead to the cell function of synthesizing DNA.
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From page 7... ...
Other workshop presentations, by John Tyson, of the Virginia Polytechnic Institute and State University, and Garrett Odell, also delved into the modeling of cellular networks. Tyson investigated the cell cycle, the sequence of events in which a growing cell replicates its components.
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From page 8... ...
As was the case with the other modeling efforts described in this summary, Tyson's process began with simple models that didn't necessarily emulate every known aspect of cellular physiology or biochemistry, and additional complexity was added only as needed to produce output that captures important features observed experimentally. Garrett Odell used a similar approach to uncover what cellular mechanism controls the formation of stripes in arthropods (see Nagy, 1998, and von Dassow et al., 2000)
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From page 9... ...
After recognizing the missing network links and representing them in the differential equations, the resulting set of equations not only produced the proper pattern, but the choice of parameters also turned out to be extremely robust. That is, the same pattern of stripes occurs over a wide range of parameter values, and it was no longer necessary to use optimization to tune the parameter set.
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