Monitoring Cellular Responses to Infection with Fluorescent Biosensors.

Fluorescent biosensors are chemically or genetically encoded reporters of cellular processes, signaling pathways, or biomolecule concentration, whose output is quantified using fluorescence microscopy or fluorescence spectrometry. These biosensors can detect the target activity or metabolites via mechanisms including conversion between nonfluorescent and fluorescent forms, changes in reporter intensity, changes in the intensity ratio across fluorescence channels, alterations to the subcellular localization of the bioreporter, and by fluorescence resonance energy transfer. Here, we describe the use of a chemical photoconverting biosensor, and genetically encoded localization and ratiometric biosensors, for monitoring the cellular and signaling processes involved in pathogen-induced apoptosis and the resulting destruction of the pathogen. While this study uses biosensors to monitor responses to infection, these approaches can be readily translated to other cellular systems and other fluorescent biosensors.