Researchers from FOM Institute AMOLF have discovered that the metabolism in cells proceeds chaotically. As this metabolism is the engine that drives all biological activity, this observed instability is relevant for diseases such as cancer, for evolution and for a range of other phenomena. The researchers published their results on 3 September 2014 in Nature.
Living cells are chemical factories that constantly take up sugars and break these down into smaller molecules. They use these smaller molecules to construct dna, proteins and cell membranes. Up until now scientists had assumed that this cellular metabolism was a regular and deterministic process.
However the research team led by Sander Tans discovered that the metabolic activity of cells fluctuates in an unpredictable manner. The researchers made these findings thanks to a new approach. Rather than attempting to measure the abundance of metabolites in individual cells, they continuously measured the quantity of an enzyme that catalyses a certain reaction. By attaching fluorescent proteins to the enzymes they could monitor both the quantity of enzymes and the reaction rate. At the same time, detailed measurements of cellular volume indicated what the consequences were for the cellular growth rate. The researchers discovered that random fluctuations in enzyme production were transmitted step-by-step to all subsequent reactions, just like a baton in a relay race.
Why this chaos?
Biological growth is therefore far more chaotic than was previously thought. This discovery elicits many new questions. For example, do cells actively try to control this chaos? And if so, how? Why has evolution failed to completely suppress this chaos? And what role does variation in the metabolism play in diseases such as cancer and diabetes?
Stochasticity of metabolism and growth at the single-cell level, Kiviet D.J., Nghe P., Walker N., Boulineau S., Sunderlikova V., Tans S.J., Nature 514, 376–379 (2014)