TGM1 and psoriasis: TGase-1 is a keratinocyte differentiation marker related to the differentiation of keratinocytes, and its expression increases in psoriatic skin.263 Nuclear β-catenin accumulation increases in keratinocytes on the epidermal base of patients with psoriasis, upregulating the activity of the transglutaminase 1 (TGase-1) promoter and leading to abnormal proliferation and differentiation of keratinocytes in the skin of psoriasis patients.