Calcium transients trigger switch-like discharge of prostaglandin E 2 in an extracellular signal-regulated kinase-dependent manner

Prostaglandin E 2 (PGE 2 ) is a key player in a plethora of physiological and pathological events. Nevertheless, little is known about the dynamics of PGE 2 secretion from a single cell and its effect on the neighboring cells. Here, by observing confluent Madin-Darby canine kidney (MDCK) epithelial cells expressing fluorescent biosensors we demonstrate that calcium transients in a single cell cause PGE 2 -mediated radial spread of PKA activation (RSPA) in neighboring cells. By in vivo imaging, RSPA was also observed in the basal layer of the mouse epidermis. Experiments with an optogenetic tool revealed a switch-like PGE 2 discharge in response to the increasing cytoplasmic Ca 2+ concentrations. The cell density of MDCK cells correlated with the frequencies of calcium transients and the following RSPA. The extracellular signal-regulated kinase (ERK) activation also enhanced the frequency of RSPA in MDCK and in vivo . Thus, the PGE 2 discharge is regulated temporally by calcium transients and ERK activity.