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ATR Kinase Activity Limits Mutagenesis and Promotes the Clonogenic Survival of Quiescent Human Keratinocytes Exposed to UVB Radiation
Author(s) -
Shaj Kavya,
Hutcherson Rebekah J.,
Kemp Michael G.
Publication year - 2019
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.13164
Subject(s) - hacat , pyrimidine dimer , biology , dna damage , dna repair , staurosporine , kinase , microbiology and biotechnology , mutagenesis , protein kinase a , biochemistry , dna , mutant , in vitro , gene
Abstract The ATR protein kinase has well‐described roles in maintaining genomic integrity during the DNA synthesis phase of the cell cycle. However, ATR function in cells that are not actively replicating DNA remains largely unexplored. Using HaCaT and telomerase‐immortalized human keratinocytes maintained in a confluent, nonreplicating state in vitro, ATR was found to be robustly activated in response to UVB radiation in a manner dependent on the nucleotide excision repair factor and DNA translocase XPB. Inhibition of ATR kinase activity under these conditions negatively impacted acute cell survival and cytotoxicity and severely inhibited the ability of UVB‐irradiated HaCaT keratinocytes to proliferate upon stimulation with growth factors. Furthermore, ATR kinase inhibition in quiescent HaCaT keratinocytes potentiated UVB mutagenesis at the hypoxanthine phosphoribosyltransferase locus. Though ATR inhibition did not impact the rate of removal of cyclobutane pyrimidine dimers from genomic DNA, elevated levels of PCNA mono‐ubiquitination and chromatin‐associated PCNA and RPA indicate that excision gap‐filling synthesis was altered in the absence of ATR signaling. These results indicate that the ATR kinase plays important roles in preventing mutagenesis and in promoting the proliferative potential of quiescent keratinocytes exposed to UVB radiation.