Innovations in the field of life sciences-2009: No. 3
3rd place according to The Scientist. Puppet Cages
The arsenal of researchers who label proteins with various dyes for subsequent observation of the processes taking place in the cell is constantly expanding, but until recently they had no opportunity to interfere with these processes at the molecular level. Recently, publications have begun to appear that describe genetically encoded photosensitive systems that allow solving such problems, but most of them require complex methods of protein engineering.
Wendell Lim and his colleagues from the University of California (San Francisco) have found the optimal solution to this problem. Usually, the photosensitive plant protein phytochrome and the phytochrome interaction factor (PIF) binding to it under the action of red light form a complex that moves into the nucleus. Infrared radiation destroys this complex.
The researchers modified the genes in such a way that when activated, this pair of proteins began to move to the cell membrane. After that, they attached the PIF to the cytoskeleton protein. As a result, exposure to directed beams of light activated PIF, which, in turn, activated the cytoskeleton protein and, thus, changed the shape of the cell. The results of this work are described in the journal Nature in the article "Spatiotemporal control of cell signaling using a light-switchable protein interaction".
According to Lim, phytochrome converts light energy into protein-protein interaction energy. Researchers can combine PIF with various proteins, which makes the system suitable for studying not only light-controlled reactions, but also other cellular processes.
The developers have transferred plasmids encoding mutant versions of phytochrome and PIF to Addgene, a non–profit plasmid repository dedicated to providing researchers with plasmids, where anyone can order them at a price of $65 per unit.