Zn influx activates ERK and Akt signaling pathways.

Zinc (Zn) is an essential metal in biology, and its bioavailability is highly regulated. Many cell types exhibit fluctuations in Zn that appear to play an important role in cellular function. However, the detailed molecular mechanisms by which Zn dynamics influence cell physiology remain enigmatic. Here, we use a combination of fluorescent biosensors and cell perturbations to define how changes in intracellular Zn impact kinase signaling pathways. By simultaneously monitoring Zn dynamics and kinase activity in individual cells, we quantify changes in labile Zn and directly correlate changes in Zn with ERK and Akt activity. Under our experimental conditions, Zn fluctuations are not toxic and do not activate stress-dependent kinase signaling. We demonstrate that while Zn can nonspecifically inhibit phosphatases leading to sustained kinase activation, ERK and Akt are predominantly activated via upstream signaling and through a common node via Ras. We provide a framework for quantification of Zn fluctuations and correlate these fluctuations with signaling events in single cells to shed light on the role that Zn dynamics play in healthy cell signaling.