Dermokine‐β impairs ERK signaling through direct binding to GRP78

Abstract

a b s t r a c tDermokine-b is abundant in stratified epithelia and in differentiating cultured keratinocytes. In this study, we investigated the role of dermokine-b in differentiation of keratinocytes. Treatment of keratinocytes or skin tumor cells with dermokine-b attenuated phosphorylation of extracellularsignal-regulated kinase (ERK). Exposure of cells to dermokine-b, as well as its carboxyl-terminus domain peptide, interrupted phosphorylation of ERK and stimulated dermokine gene expression. Inhibition of ERK signaling by its specific inhibitor also increased dermokine expression level. A combination of chemical cross-linking and immunoprecipitation, followed by proteomics analyses, identified glucose-regulated protein 78 (GRP78) as a dermokine-b-associated protein. Blockage of GRP78 expression by a specific siRNA abrogated actions of dermokine-b. These findings provide novel insights into the physiological significance of dermokine-b in the epidermis.

Mice deficient for the epidermal Dermokine β and γ display transient cornification defects

“…According to recently published data concerning overexpression of DMKN b in human keratinocytes, the absence of Dmkn b would be expected to lead to an increase in Erk phosphorylation resulting in a decrease in Dmkn and Ivl gene expression (Higashi et al, 2012). By contrast, our results show no difference in the balance between Erk and phosphorylated Erk in the skin of KO compared to control mice.…”

“…3C). It has previously been shown that DMKN b decreases the phosphorylation of ERK1/2 and subsequently increases caspase activity in cultured human keratinocytes (Higashi et al, 2012). Our analysis of the phosphorylation level of ERK1/2 by immunoblotting ( Fig.…”

“…This suggests that DMKN b and c could take part in the pathogenesis of this bacteria (Xiang et al, 2012). In another study, experiments using cultured normal human epidermal keratinocytes revealed that exogenous DMKN b inhibited phosphorylation of extracellular-signal-regulated (ERK)1/2 and increased the expression of involucrin (IVL), suggesting that DMKN b is involved in keratinocyte differentiation through regulation of the ERK signaling pathway (Higashi et al, 2012). More recently, a putative role of Dmkn b during mouse skin wound healing has been reported.…”

Expression of the Clustered NeuAcα2–3Galβ O-Glycan Determines the Cell Differentiation State of the Cells

“…Expressions of human GALNT1 and LARGE were quantified using MESA Blue qPCR Mastermix (Eurogentec, Seraing, Belgium) as previously described (14). The PCR primers used were as follows: GALNT1 forward, 5Ј-ATGACCTATG-GTGGGTTCAACT-3Ј and reverse, 5Ј-CTGACAGGAAGAG-TCCGATCA-3Ј; LARGE forward, 5Ј-TCCGAGCAGTGCTAC-AGAGA-3Ј and reverse, 5Ј-TTGCGAAAAAACTCCACATG-3Ј.…”

Matrix Metalloproteinase 10 Degradomics in Keratinocytes and Epidermal Tissue Identifies Bioactive Substrates With Pleiotropic Functions*

“…Moreover, recombinant DMKN inhibited ERK phosphorylation in cultured keratinocytes and delayed wound closure in mice (75,76). However, the mechanisms of DMKN activity in keratinocyte differentiation and inflammatory skin diseases remain to be determined.…”