MAPK3 and Keratoconjunctivitis sicca: Both p-Erk1 or 2 and total Erk1 or 2 were up-regulated in the saline-treated dry eye group, thereby leading to a minimal increment in the ratio of p-Erk1 or 2 over total Erk1 or 2 compared to the saline controls (Fig. 7B,D).