Gfp Sensors

The green fluorescent protein (GFP) and related genetically-encoded fluorescent proteins have had a major impact in cell biology. GFP has diverse applications in studies of protein localization, dynamics, interactions and regulation. GFP is targetable to specific cellular sites in cell culture models and in vivo in a wide variety of organisms. A unique application of fluorescent proteins is their engineering as real-time cellular sensors of pH, ion concentrations, second messengers, enzyme activities and other parameters. Compared to classical chemical probes, genetically-encoded fluorescent proteins permit stable non-invasive staining of specific subcellular sites in cell culture models and in vivo with little or no cellular toxicity. This chapter reviews the paradigms that have been developed for engineering of GFP-based sensors, applications of available sensors, and directions for further sensor development.