Evolution and Regulation of Metabolic Networks
The analysis of metabolic processes, gene expression patterns, and protein-protein interactions in different organisms indicates that cellular metabolic networks have a scale-free and hierarchical topology described by power laws. The dynamics of these networks might be produced by a fractal organization of an autoregulatory loop, named metabolic hypercycle, between opposite redox processes of anabolic and catabolic types. This fractal architecture allows the formation of a long range correlated state of cellular networks which is globally regulated by a critical hub sensitive to the redox state. In prokaryotic cells this fundamental regulator is generally a two-component kinase system while in eukaryotic cells it is likely that casein kinase-2 and glycogen synthase kinase-3 play a central role in metabolism control. Both prokaryotes and eukaryotes share the same conserved sequence signatures, the PAS domain, in the main sensors of the changes in redox potential. Many experimental data support the hypothesis that the developmental pathways of cells and complex organisms are the results of conserved biological clocks based on metabolic hypercycles organized in fractal networks.
KeywordsMetabolic Network Cellular Network Circadian Clock Fractal Network Major Histocompatibility Complex Allele
Unable to display preview. Download preview PDF.
- Damiani G., and Della Franca P. Morphé and Evolution. Biology Forum 1997; 90: 227–66.Google Scholar
- Damiani G. Il gioco della vita, la teoria binaria dell’Universo fisico. Editrice Italiana Audiovisivi, Roma, 1984.Google Scholar
- Damiani G. Evolutionary meaning, functions and morphogenesis of branching structures in biology. In: Nonnenmacher T.F., Losa G.A., and Weibel E.R., eds. Fractals in biology and medicine Vol. 1, Birkhauser-Verlag, Basel, 1994; 104–15.Google Scholar
- Damiani G. Evolution of life in a fractal Universe. In: Losa G.A., Merlini D., Nonnenmacher T.F., and Weibel E.R., eds. Fractals in biology and medicine Vol. 2, Birkhauser-Verlag, Basel, 1998; 169–87.Google Scholar
- Damiani G. Metabolic Hypercycles, Universality and Fractals in Biological Evolution. In: Losa G.A., Merlini D., Nonnenmacher T.F., and Weibel E.R., eds. Fractals in biology and medicine Vol. 3, Birkhauser-Verlag, Basel, 2002; 259–69.Google Scholar
- Barbasi AL, Oltvai ZN. Network biology: understanding the cell’s functional organization. Nat Rev Genet. 2004; 52:101–13.Google Scholar
- May RM. Stability and complexity in model ecosystems: Monographs in population biology. Princeton University Press, Princeton, 1974.Google Scholar
- Szent-Gyorgyi A. The Living State — With Observation on Cancer. Academic Press, New York-London, 1972.Google Scholar