Delta Np63 transcriptionally regulates ATM to control p53 Serine-15 phosphorylation

Ashley L Craig, Jitka Holcakova, Lee E Finlan, Marta Nekulova, Roman Hrstka, Nuri Gueven, James DiRenzo, Graeme Smith, Ted R Hupp, Borivoj Vojtesek

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

Background: Delta Np63 alpha is an epithelial progenitor cell marker that maintains epidermal stem cell self-renewal capacity. Previous studies revealed that UV-damage induced p53 phosphorylation is confined to Delta Np63 alpha-positive cells in the basal layer of human epithelium. Results: We now report that phosphorylation of the p53 tumour suppressor is positively regulated by Delta Np63 alpha in immortalised human keratinocytes. Delta Np63 alpha depletion by RNAi reduces steady-state ATM mRNA and protein levels, and attenuates p53 Serine-15 phosphorylation. Conversely, ectopic expression of Delta Np63 alpha in p63-null tumour cells stimulates ATM transcription and p53 Serine-15 phosphorylation. We show that ATM is a direct Delta Np63 alpha transcriptional target and that the Delta Np63 alpha response element localizes to the ATM promoter CCAAT sequence. Structure-function analysis revealed that the Delta Np63-specific TA2 transactivation domain mediates ATM transcription in coordination with the DNA binding and SAM domains. Conclusions: Germline p63 point mutations are associated with a range of ectodermal developmental disorders, and targeted p63 deletion in the skin causes premature ageing. The Delta Np63 alpha-ATM-p53 damage-response pathway may therefore function in epithelial development, carcinogenesis and the ageing processes.
Original languageEnglish
Article number195
Number of pages13
JournalMolecular Cancer
Publication statusPublished - Jul 2010


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