DSG1 and pemphigus: Antibodies specific for Dsg3 such as the mouse pemphigus antibody AK23 (16) similar to m-PV-IgG was sufficient to activate p38MAPK and Src whereas Ca2+ influx and ERK activation were detectable only when antibodies against Dsg1 were present in patients IgG fractions such as mc-PV-IgG and PF-IgG (15).