MAPK3 and psoriasis: A prior study found an increased level of phosphorylated MSK1 (Ser376) in psoriatic lesions.209 In psoriasis, a high level of IL-6 can lead to increased activation of p-ERK1/2.210 Keratin16 (KRT16), a hyperproliferation-associated keratin in keratinocytes, has proven to enhance keratinocyte proliferation and VEGF secretion by activating and phosphorylating the ERK signaling pathway.211 Furthermore, DUSP1/MKP-1, a negative regulator of the MAPK pathway, is found to be downregulated in psoriasis.