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Functional networks in mammalian cells

Part 3. Proteomics

3.8. Systems Biology

Specialist Review

  1. Yuguang Xiong,
  2. Ravi Iyengar

Published Online: 15 JAN 2005

DOI: 10.1002/047001153X.g308209

Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics

Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics

How to Cite

Xiong, Y. and Iyengar, R. 2005. Functional networks in mammalian cells. Encyclopedia of Genetics, Genomics, Proteomics and Bioinformatics. 3:3.8:108.

Author Information

  1. Mount Sinai School of Medicine, Department of Pharmacology and Biological Chemistry, NY, USA

Publication History

  1. Published Online: 15 JAN 2005


The basic functional unit of multicellular organism is the cell. Cells are complex systems that perform many required fundamental functions such as environmental adaptation, energy utilization, proliferation, and differentiation in a regulated manner. Even cell death is often a controlled process. Cellular functions involve numerous components participating in a variety of processes. A critical aspect for normal cell functionality is the rigorous control of all cellular processes that may take place at different cellular locations at different rates and at different times. Such regulation is achieved by a central intracellular signaling network that receives and processes signals from both extracellular and intracellular sources. The processed signals are then used to regulate the different cellular machines such that they can function co-operatively to evoke complex physiological responses. In order to achieve reliable functionality, the cell has developed multiple redundant systems that can regulate the cellular machines. Additionally, the systems are arranged in a modular fashion such that disturbances do not substantially propagate between modules. This architecture leads to a complex system where both robustness and fragility are dynamically balanced.


  • cell signaling networks;
  • cellular machines;
  • design principles;
  • complexity;
  • dynamics;
  • robustness/fragility