Protein phosphatase-1 is involved in the maintenance of normal homeostasis and in UVA irradiation-induced pathological alterations in HaCaT cells and in mouse skin

Dóra Dedinszki, Adrienn Sipos, Andrea Kiss, Róbert Bátori, Zoltán Kónya, László Virág, Ferenc Erdo'di, Beáta Lontay

Research output: Contribution to journalArticle

5 Citations (Scopus)


The number of ultraviolet (UV) radiation-induced skin diseases such as melanomas is on the rise. The altered behavior of keratinocytes is often coupled with signaling events in which Ser/Thr specific protein kinases and phosphatases regulate various cellular functions. In the present study the role of protein phosphatase-1 (PP1) was investigated in the response of human keratinocyte (HaCaT) cells and mouse skin to UV radiation. PP1 catalytic subunit (PP1c) isoforms, PP1cα/γ and PP1cδ, are all localized to the cytoskeleton and cytosol of keratinocytes, but PP1cδ was found to be dominant over PP1α/γ in the nucleus. PP1c-silencing in HaCaT cells decreased the phosphatase activity and suppressed the viability of the cells. Exposure to a 10J/cm2 UVA dose induced HaCaT cell death and resulted in a 30% decrease of phosphatase activity. PP1c-silencing and UVA irradiation altered the gene expression profile of HaCaT cells and suggested that the expression of 19 genes was regulated by the combined treatments with many of these genes being involved in malignant transformation. Microarray analysis detected altered expression levels of genes coding for melanoma-associated proteins such as keratin 1/10, calcium binding protein S100A8 and histone 1b. Treatment of Balb/c mice with the PP1-specific inhibitor tautomycin (TM) exhibited increased levels of keratin 1/10 and S100A8, and a decreased level of histone 1b proteins following UVA irradiation. Moreover, TM treatment increased pigmentation of the skin which was even more apparent when TM was followed by UVA irradiation. Our data identify PP1 as a regulator of the normal homeostasis of keratinocytes and the UV-response.

Original languageEnglish
Pages (from-to)22-33
Number of pages12
JournalBiochimica et Biophysica Acta - Molecular Basis of Disease
Issue number1
Publication statusPublished - Jan 1 2015



  • Gene expression
  • Histone 1b
  • Keratin 1/10
  • Keratinocyte
  • Protein phosphatase-1
  • UV irradiation

ASJC Scopus subject areas

  • Molecular Medicine
  • Molecular Biology

Cite this