MAPK8 and psoriasis: The MAPK kinases, involved in the pathogenesis of psoriasis, control several important functions within the cell, such as cell proliferation, differentiation, gene expression, and apoptosis in keratinocytes.[22, 23] AKT-mediated signaling is functionally involved in keratinocyte transformation, differentiation and proliferation.[19, 24, 25] hS100A7 treatment activates p38 MAPK, JNK and AKT, but not ERK kinase (Fig 2A).