pHluorins: A Versatile Tool for the Study of Vesicle Biology

The study of synaptic vesicle exocytosis and endocytosis in neurons has traditionally relied upon low-spatial resolution electrophysiological techniques. Recent advances using targeted fluorescent probes have afforded new opportunities for the exploration of these processes. In particular, the development of a family of pH-sensing probes known as “pHluorins” has enabled the reporting of exo- and endocytotic events with exceptional spatial and good temporal resolution. This review highlights the transformative impact of pHluorins on the study of vesicle biology, describing the many creative ways that they have been used. We discuss specific experimental approaches by which pHluorins either alone or in combination with other methods have helped reveal new features of neuronal function. We also highlight areas where pHluorins have the potential to further advance our understanding of neuronal cell biology.