UCSF

Cell biology's leading lightsGreen fluorescent protein and other genetically encodable optical reporters have revolutionized the study of cell function. Now Levskaya et al. describe a technology that adds a new dimension to cell biology by incorporating light-activated proteins from plants into mammalian cell signalling systems, leading to cells whose morphology and behaviour can be controlled by light. The system uses a reversible protein–protein interaction module from the Arabidopsis phytochrome-signalling network to reversibly translocate activators of the Rho-family GTPases to the plasma membrane. In principle, this advance makes it possible to design a variety of light-programmable reagents for a new generation of perturbative cell biology experiments.