Title
Identification of Biochemical Network Modules Based on Shortest Retroactive Distances.
Abstract
Modularity analysis offers a route to better understand the organization of cellular biochemical networks as well as to derive practically useful, simplified models of these complex systems. While there is general agreement regarding the qualitative properties of a biochemical module, there is no clear consensus on the quantitative criteria that may be used to systematically derive these modules. In this work, we investigate cyclical interactions as the defining characteristic of a biochemical module. We utilize a round trip distance metric, termed Shortest Retroactive Distance (ShReD), to characterize the retroactive connectivity between any two reactions in a biochemical network and to group together network components that mutually influence each other. We evaluate the metric on two types of networks that feature feedback interactions: (i) epidermal growth factor receptor (EGFR) signaling and (ii) liver metabolism supporting drug transformation. For both networks, the ShReD partitions found hierarchically arranged modules that confirm biological intuition. In addition, the partitions also revealed modules that are less intuitive. In particular, ShReD-based partition of the metabolic network identified a 'redox' module that couples reactions of glucose, pyruvate, lipid and drug metabolism through shared production and consumption of NADPH. Our results suggest that retroactive interactions arising from feedback loops and metabolic cycles significantly contribute to the modularity of biochemical networks. For metabolic networks, cofactors play an important role as allosteric effectors that mediate the retroactive interactions.
Year
DOI
Venue
2011
10.1371/journal.pcbi.1002262
PLOS COMPUTATIONAL BIOLOGY
Field
DocType
Volume
Complex system,Biology,Metric (mathematics),Intuition,Metabolic network,Liver metabolism,Bioinformatics,Modularity
Journal
7
Issue
ISSN
Citations 
11
1553-734X
5
PageRank 
References 
Authors
0.50
12
3
Name
Order
Citations
PageRank
Gautham Vivek Sridharan191.28
Soha Hassoun2535241.27
Kyongbum Lee3707.40