Bio-switches: what makes them robust?
Ideas of how a system of interacting enzymes can act as a switch are based on the concept of bistability of a biochemical network. This means that, because of the very structure of a signaling pathway, the system can be in one of two stable steady states: active or inactive. Switching from one state to another may then occur in response to external stimuli or as a result of internal development. However, the bistability of a biochemical network might not be robust enough to be the sole mechanism behind bio-switching. On the basis of recent experimental data on the cell-cycle G2/M transition during starfish oocyte meiotic maturation, it is shown that cooperative phenomena--such as phase changes associated with clustering, dissolution of aggregates and so on--may play central roles in providing a decisive and irreversible transition.
Slepchenko
Boris M
BM
Department of Cell Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, Connecticut 06030-1507, USA. boris@neuron.uchc.edu
Terasaki
Mark
M
D000818:Animals; D004789:Enzyme Activation / Q000502:physiology*; D025461:Feedback, Physiological / Q000502:physiology; D008540:Meiosis / Q000502:physiology; D008954:Models, Biological; D009865:Oocytes / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D013215:Starfish / Q000502:physiology*