GADD45A and psoriasis: GADD45α has been shown to participate in DNA demethylation of the promoter of Ubiquitin C-terminal hydrolase L1(UCHL1); as a deubiquitinase, UCHL1 is involved in the controls keratinocyte proliferation and inflammation in psoriasis; hypermethylated UCHL1 promoter was found in the psoriatic lesioned skin and associated with a lower level of GADD45α protein, indicating that the demethylation of UCHL1promoter by GADD45α increases the expression of UCHL1 protein in psoriatic damaged skin (156).