MAPK3 and glaucoma: [50–52] One of the ways by which the Erk1/2 pathway protects cells from apoptotic events is by degrading Bim through phosphorylation of specific serine residues.[53, 54] It is tempting to speculate that activating the Erk1/2 pathway through the use of agents like KATP channel openers may be a means to protecting retinal ganglion cells during glaucoma.