MEK-ERK signaling in adult newt retinal pigment epithelium cells is strengthened immediately after surgical induction of retinal regeneration

► ERK-mediated signaling activity in RPE cells is elevated quickly (in 30 min) upon retinectomy. ► MEK-ERK signaling is intensified by itself through up-regulation of the expression of constituent molecules in the pathway. ► Blockade of initial MEK-ERK signaling inhibits cell-cycle re-entry of RPE cells.