Cells measure environmental signals with considerable accuracy
Biological systems, such as bacteria and human cells, can measure chemical concentrations with an unprecedented precision. This enables them to respond adequately to their environment. Researchers from the FOM Institute AMOLF in Amsterdam have discovered how cellular systems perform these measurements and that this happens far more accurately than had previously been assumed. The results from this research were published today in the leading scientific journal Physical Review Letters.
Measuring environmental signals
All living cells must be able to respond to signals from their environment. That applies to bacteria that search of food or human cells that differentiate themselves into a brain cell, for example. These signals are made up of concentrations of molecules. Cells measure the concentrations via receptor proteins on their surface that bind to the molecules. However, the measurements are disrupted because the molecules intermittently come into contact with the receptor proteins and then do not always bind to them: the binding is a process of chance. Consequently cells must filter out as much noise as possible so that they can still accurately determine the concentration of the molecules. Cells do this by performing several measurements and then taking the average.
Determining the accuracy
How cells realised the averaging process was something of a mystery. Scientists assumed that cells accorded each measurement the same weighting in the averaging process. However, the researchers from AMOLF have now discovered that cells give each measurement a different weighting. They have also demonstrated that this increases the supposed fundamental limit of the accuracy with which concentrations can be measured. Cells can therefore measure concentrations far more accurately than had previously been assumed.
Reference
Chris Govern and Pieter Rein ten Wolde
Fundamental Limits on Sensing Chemical Concentrations with Linear Biochemical Networks
Phys. Rev. Lett. (2012)
Contact
Dr. Chris Govern +31 (0)20 754 71 54
Prof. Pieter Rein ten Wolde +31 (0)20 754 72 81