1. MiTF links Erk1/2 kinase and p21 CIP1/WAF1 activation after UVC radiation in normal human melanocytes and melanoma cells.
- Author
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Liu, Feng, Singh, Amarinder, Yang, Zhen, Garcia, Angela, Kong, Yu, and Meyskens, Frank L, Jr
- Subjects
Cell Line ,Tumor ,Cyclin-Dependent Kinase Inhibitor p21: metabolism ,Humans ,Melanocytes: enzymology ,metabolism ,radiation effects ,Melanoma: enzymology ,metabolism ,pathology ,Microphthalmia-Associated Transcription Factor: metabolism ,Mitogen-Activated Protein Kinase 1: metabolism ,Mitogen-Activated Protein Kinase 3: metabolism ,Phosphorylation ,Proteasome Endopeptidase Complex: metabolism ,Serine: metabolism ,Ultraviolet Rays ,alanine ,cyclin dependent kinase inhibitor 1 ,micropthalmia associated transcription factor ,mitogen activated protein kinase 1 ,mitogen activated protein kinase 3 ,serine ,transcription factor ,unclassified drug ,CDKN1A protein ,human ,cyclin dependent kinase inhibitor 1A ,MAPK1 protein ,human ,microphthalmia associated transcription factor ,MITF protein ,human ,mitogen activated protein kinase 1 ,mitogen activated protein kinase 3 ,proteasome ,amino acid substitution ,article ,cell cycle arrest ,cell cycle G1 phase ,cell death ,cell survival ,controlled study ,genomic instability ,human ,human cell ,melanocyte ,melanogenesis ,melanoma cell ,protein degradation ,protein expression ,protein phosphorylation ,radiation exposure ,signal transduction ,site directed mutagenesis ,ultraviolet C radiation ,enzymology ,melanoma ,metabolism ,pathology ,phosphorylation ,tumor cell line ,ultraviolet radiation ,Cell Line ,Tumor ,Cyclin-Dependent Kinase Inhibitor p21 ,Humans ,Melanocytes ,Melanoma ,Microphthalmia-Associated Transcription Factor ,Mitogen-Activated Protein Kinase 1 ,Mitogen-Activated Protein Kinase 3 ,Phosphorylation ,Proteasome Endopeptidase Complex ,Serine ,Ultraviolet Rays ,alanine ,cyclin dependent kinase inhibitor 1 ,micropthalmia associated transcription factor ,mitogen activated protein kinase 1 ,mitogen activated protein kinase 3 ,serine ,transcription factor ,unclassified drug ,CDKN1A protein ,human ,cyclin dependent kinase inhibitor 1A ,MAPK1 protein ,human ,microphthalmia associated transcription factor ,MITF protein ,human ,mitogen activated protein kinase 1 ,mitogen activated protein kinase 3 ,proteasome ,amino acid substitution ,article ,cell cycle arrest ,cell cycle G1 phase ,cell death ,cell survival ,controlled study ,genomic instability ,human ,human cell ,melanocyte ,melanogenesis ,melanoma cell ,protein degradation ,protein expression ,protein phosphorylation ,radiation exposure ,signal transduction ,site directed mutagenesis ,ultraviolet C radiation ,enzymology ,melanoma ,metabolism ,pathology ,phosphorylation ,tumor cell line ,ultraviolet radiation ,Cell Line ,Tumor ,Cyclin-Dependent Kinase Inhibitor p21 ,Humans ,Melanocytes ,Melanoma ,Microphthalmia-Associated Transcription Factor ,Mitogen-Activated Protein Kinase 1 ,Mitogen-Activated Protein Kinase 3 ,Phosphorylation ,Proteasome Endopeptidase Complex ,Serine ,Ultraviolet Rays - Abstract
As a survival factor for melanocytes lineage cells, MiTF plays multiple roles in development and melanomagenesis. What role MiTF plays in the DNA damage response is currently unknown. In this report we observed that MiTF was phosphorylated at serine 73 after UVC radiation, which was followed by proteasome-mediated degradation. Unlike after c-Kit stimulation, inhibiting p90RSK-1 did not abolish the band shift of MiTF protein, nor did it abolish the UVC-mediated MiTF degradation, suggesting that phosphorylation on serine 73 by Erk1/2 is a key event after UVC. Furthermore, the MiTF-S73A mutant (Serine 73 changed to Alanine via site-directed mutagenesis) was unable to degrade and was continuously expressed after UVC exposure. Compared to A375 melanoma cells expressing wild-type MiTF (MiTF-WT), cells expressing MiTF-S73A mutant showed less p21 WAF1/CIP1 accumulation and a delayed p21 WAF1/CIP1 recovery after UVC. Consequently, cells expressing MiTF-WT showed a temporary G1 arrest after UVC, but cells expressing MiTF-S73A mutant or lack of MiTF expression did not. Finally, cell lines with high levels of MiTF expression showed higher resistance to UVC-induced cell death than those with low-level MiTF. These data suggest that MiTF mediates a survival signal linking Erk1/2 activation and p21 WAF1/CIP1 regulation via phosphorylation on serine 73, which facilitates cell cycle arrest. In addition, our data also showed that exposure to different wavelengths of UV light elicited different signal pathways involving MiTF.
- Published
- 2010