Probes for monitoring regulated exocytosis

Regulated secretion is a fundamental cellular process that serves diverse functions in neurobiology, endocrinology, immunology, and numerous other aspects of animal physiology. In response to environmental or biological cues, cells release contents of secretory granules into an extracellular medium to communicate with or impact neighboring or distant cells through paracrine or endocrine signaling. To investigate mechanisms governing stimulus-secretion coupling, to better understand how cells maintain or regulate their secretory activity, and to characterize secretion defects in human diseases, probes for tracking various exocytotic events at the cellular or sub-cellular level have been developed over the years. This review summarizes different strategies and recent progress in developing optical probes for monitoring regulated secretion in mammalian cells.