title: Simplified models of biological networks.
abstract: The function of living cells is controlled by complex regulatory networks that are built of a wide diversity of interacting molecular components. The sheer size and intricacy of molecular networks of even the simplest organisms are obstacles toward understanding network functionality. This review discusses the achievements and promise of a bottom-up approach that uses well-characterized subnetworks as model systems for understanding larger networks. It highlights the interplay between the structure, logic, and function of various types of small regulatory circuits. The bottom-up approach advocates understanding regulatory networks as a collection of entangled motifs. We therefore emphasize the potential of negative and positive feedback, as well as their combinations, to generate robust homeostasis, epigenetics, and oscillations.
authors.affiliation: Niels Bohr Institute, DK-2100, Copenhagen, Denmark. sneppen@nbi.dk
authors.forename: Kim
authors.initials: K
authors.lastname: Sneppen
authors.forename: Sandeep
authors.initials: S
authors.lastname: Krishna
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Semsey
mesh_terms: D000818:Animals; D025461:Feedback, Physiological; D053263:Gene Regulatory Networks; D006801:Humans; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D015398:Signal Transduction; D049490:Systems Biology