Microbiologist Wendell Lim and his colleagues at the University of California at San Francisco are attempting to control living cells by rewriting their internal programming. This is possible, Lim realized, because proteins in a cell function like transistors on a silicon chip. They are modular and, depending on how they are combined, convey specific instructions: grow, migrate, or fight pathogens, for instance. The researchers tinkered with N-WASP, a protein that functions as a switch to activate cellular movement. By splicing genes for the original protein with ones that code for proteins containing different instructions, the researchers created a modified version of N-WASP. Lim plans to insert this synthetic switch, and others he has developed, into living cells to alter how they function.
Other researchers have tried changing cell behavior by creating protein switches from scratch, but Lim’s approach—mixing and matching naturally existing proteins—may be more versatile and practical: “It can be useful as a biotechnology device or for repairing cells in humans. And it appears relatively easy to do.” Eventually, Lim hopes that reprogrammed cells will measure glucose levels in the pancreases of diabetics and trigger a biological insulin response, or even cure cancer. “Imagine if we could create circuits that detect defects in cancer cells and then turn on pathways that lead to the death of those cells,” he says.