A New Way to Count Proteins in Living Cells

Stepwise Photobleaching

One fluorescence microscopy method for counting protein molecules is stepwise photobleaching. This approach relies on the irreversible bleaching of individual fluorophores, which can be detected as a stepwise decrease in the fluorescence intensity of the sample. However, stepwise photobleaching can be time-consuming and can damage the sample.

A New Method

Scientists have developed a new way of counting labelled proteins in living cells that could become a standard and valuable tool in the field of quantitative biology. The method, called "pair correlation analysis," is based on the idea that the average distance between two fluorescently labelled proteins is proportional to the square root of the number of proteins in the cell.

Pair correlation analysis is much faster than stepwise photobleaching and does not damage the sample. It can also be used to count proteins in 3D, which is not possible with stepwise photobleaching.

Conclusion

Pair correlation analysis is a powerful new tool for counting proteins in living cells. It is fast, accurate, and non-destructive. This method is likely to become a standard tool in the field of quantitative biology.