MAPK1 and psoriasis: Activation of the p38/JNK/ERK MAPKs (Shi et al., 2018; Liang et al., 2019; Sakurai et al., 2019) and PI3K/AKT (Engelman et al., 2006; Li et al., 2019) signaling pathways contributes to psoriasis exacerbation and disturbed regulation of proliferation and apoptosis in activated keratinocytes.