DSG1 and pemphigus: Because we observed that ERK activation by pemphigus autoantibodies correlated with presence of autoantibodies targeting Dsg1 but not with expression of Dsg3 in keratinocytes (17, 21), we speculate that inhibition of ERK signaling may have been effective to ameliorate skin blistering at least in part via stabilization of apical desmosomes of basal keratinocytes.