Site-specific labeling of proteins in living cells using synthetic fluorescent dyes

Abstract

Fluorescent probes provide the inroads to the territory of modern cellular imaging. Recent developments in microscopy have sparked the application of new optical properties of fluorescent probes. Even though the palette of genetically encoded fluorophores has dramatically expanded in recent years, synthetic probes offer a wide choice of spectral and sensing properties that can be custom-tailored for the visualization of events and states. Site-directed in vivo labeling of proteins links the specificity of molecular biology with the versatility of spectral properties offered by synthetic fluorophores. These approaches will therefore take up a prominent position alongside the fluorescent proteins. This review outlines recent developments in probes and in vivo-labeling approaches and their application by addressing protein interaction sensing using environmentally sensitive dyes, high-contrast and sensitive FRET imaging by lock-in detection of photochromic dyes, and the in vivo labeling of endogenous proteins by the use of chromobodies.