Shedding light on cell signaling: interpretation of FRET biosensors.

This Perspective compares recently developed approaches for studying live-cell signaling dynamics. It is now possible not only to study the changing localizations of proteins within living cells but to correlate these dynamics with quantitation of protein activities, including ligand interactions and phosphorylation. Initial applications of an increasingly varied toolchest of techniques have revealed strengths and weaknesses in each approach, clarifying which tool is best for which job.