mitogen activated protein kinase signaling pathway Erk5 MAPK signaling pathway Bmk1 MAPK signaling pathway ERK5 cascade PW:0000603 Signalling to ERK5 The Erk5 pathway, also known as the big MAP kinase, is activated by various stresses but not by inflammatory cytokines. In HeLa and PC12 cells, the pathway can be activated by growth factors. pathway