c-Myc protein is degraded in response to UV irradiation

Sébastien Britton, Bernard Salles and Patrick Calsou

volume 7 | issue 1

1 January 2008
Pages: 63 - 70

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The c-MYC proto-oncogene encodes a transcription factor that is critical for cell growth and proliferation. It is one of the genes frequently altered in cancer cells in which it exhibits constitutive activity. The half-life of c-MYC is very short in quiescent cells due to ubiquitin-mediated proteolysis. We report here the rapid and dose-dependent decline of c-MYC protein level after UV-irradiation in various human and rodent cells. This decline is due to a proteasomal degradation of c-MYC protein and does not require the binding sites for the FBW7 and SKP2 ubiquitin ligases. Together, our data exclude a prominent role for the stress-responsive kinase PAK2, for the major phosphoinositide 3-kinase related protein kinases ATR, ATM, DNA-PK and mTOR and for ERK, JNK and p38 mitogen activated protein kinases in this UV-induced degradation process. We propose that c-MYC degradation is part of the global cell response to UV-damage, complementary to the accumulation and activation of the p53 transcription factor. By contributing to the replication arrest after infliction of lesions to the genome, the induced degradation of c-MYC may be part of the safeguard mechanisms maintaining genome stability.

Authors

Sébastien Britton

Institut de Pharmacologie et de Biologie Structurale, CNRS-Université de Toulouse; Toulouse, France

Bernard Salles

Université toulouse III/CNRS UMR 5089; Toulouse, France

Patrick Calsou