In addition to using light to illuminate and study cellular processes, researchers at the University of California, San Francisco (UCSF) have developed a light-activated protein that uses light to actually control cell movement and other intracellular processes. Similar research has been led by Klaus Hahn and colleagues at the University of North Carolina, Chapel Hill.
The UCSF research uses genetically encoded plant proteins that respond to red and infrared light. When these proteins are inserted into mammalian cells, 650 and 750 nm light can be used to direct the movement of a cell in a particular direction, to stop on command, or to control certain cellular functions such as the movement of proteins in and out of the cell membrane. These proteins are normally used in plant cells to direct a plant to move into the sun (shade avoidance) to maximize photosynthesis. In one case, a portion of a cell injected with the protein was illuminated by 650 nm light and was stretched out up to 30 µm from the main body of the cell, remaining in that position even after the light was withdrawn. The researchers say this indicates the future possibility of programmatically specifying cell geometries and intercellular connections with light. Contact Wendell A. Lim at [email protected].