Researchers at the Rockefeller University have developed a technique to help analyze the course of specific proteins in the cell by harnessing the properties of polarized light. The team measured the nuclear pore composite, a protein cluster, which leads to a cell's nucleus, to understand how it works.
According to Sandy Simon, head of the Laboratory of Cellular Biophysics, the technique helps them to understand how the protein clusters are placed in relation to each other. This could explain the complex functions, helping its application in multi-protein complexes including DNA transcription, protein synthesis or viral reproduction.
The technique was developed by Simon with the postdoctoral student Alexa Mattheyses, graduate student, Claire Atkinson and Martin Kampmann at the University of California, San Francisco. It uses the properties of polarized light to reveal how particular proteins are arrayed in relation to each other. Fluorescent markers were genetically fixed to single parts of the complex. The cell's replication of the gene was replaced with the one having the fluorescent tag. Customized microscopes measured the course of the light waves of the fluorescent marked proteins. The measurements were used along with the existing data of the complex.
The technique was used to study both budding yeast and human cells. Multiple replications of a building block, the Y-shaped subcomplex in human cells was shown to align head-to-tail. The fluorescence in the proteins can be measured in live cells, so that it could reveal how proteins respond to different environments. It will also help study how the pore looks and works both when it is inert and active.
The research paper appeared recently in The Biophysical Journal.