Biomedical Engineering Reference
In-Depth Information
Figure 8
. From the
particular
to the
universal
. The bottom (level 1) of the pyramid shows
schematic representations of the cell's functional organization: genome, transcriptome, pro-
teome, and metabolome. Insights into the cell's organization can be obtained if we consider
the components to be linked by functional relationships, such as regulatory motifs and meta-
bolic pathways (level 2). In turn, they are the building blocks of operational modules (level 3),
which are nested and considerably blurred, generating a scale-free hierarchical architecture
(level 4). Although the individual components are unique, the topological properties of bio-
logical networks share astounding similarities. This suggests that universal organizing princi-
ples apply to all kinds of complex networks (38).
protein interactions, the determination of modules and highly connected proteins
will become a major issue in the fast and effective identification of potential
drug targets.
The recent progress in biological networks has successively uncovered the
skeleton and organization of networks, offering important insights about the
assembly and functionality of components and subnetworks. In the future we
will need to go several steps further, addressing the dynamic aspects of various
cellular networks (see also this volume, Part III, chapter 2.1, by Huang, Sultan,
and Ingber). The analysis of fluxes and fluctuations along the links in metabolic
