FLIPPING OUT: Researchers have designed kinases that can be inactivated and activated by light. In violet light, engineered green fluorescent domains (called pdDronpa) dimerize, glow, and block the enzyme’s active site (top). In blue light, the domains break into monomers, lose their fluorescence, and uncage the kinase’s active site (bottom).© GEORGE RETSECK
Controlling a protein’s activity with light enables spatial and temporal regulation that would be practically impossible otherwise. Such fine control is desirable for teasing out the molecular details of cellular processes and for initiating the actions of therapeutic proteins in precise locations in the body.
Molecular biologists, including Michael Lin of Stanford University, are hard at work developing and improving such protein technology. And Lin’s latest approach is “particularly remarkable,” says Harald Janovjak of the Institute of Science and Technology in Austria.
The principal component of Lin’s system is an engineered protein dimer (a green fluorescence protein) that, upon exposure to blue light (500 nm), converts to two monomers. Upon violet light (400 nm) exposure, the monomers revert to the dimeric form. Without violet light, ...
