Abstract B09: DNA damage inducible phosphorylation of ATR at threonine 1989 and quantitative analysis of the effect of ATR inhibition on DNA damage signaling using PTMScan

DNA repair pathways and checkpoint control are crucial in the maintenance of genome integrity. Agents that cause DNA damage, and agents that perturb DNA repair pathways, have been used successfully in the treatment of human cancer.The PI3K-like protein kinases ATR (ATM and Rad3-related) and ATM (ataxia telangiectasia mutated) are critical regulators of the DNA damage response (DDR), signaling to downstream effector molecules that in turn regulate cellular responses such as DNA repair, cell cycle arrest, and cell death.ATM is activated in response to DNA damage in part via autophosphorylation at serine 1981. ATR was long thought to exist in a constitutively active state in cells, with DNA damage-induced signaling occurring via recruitment of ATR to single stranded DNA and sites of replication stress. Recent work, however, has shown autophosphorylation of ATR at threonine 1989, a homologous site to ATM Ser1981. Like ATM Ser1981, phosphorylation of ATR Thr1989 occurs in response to DNA damage, indicating that phosphorylation at this site is important in ATR-mediated signaling.We have generated highly specific antibodies to both ATM Ser1981 and ATR Thr1989. Using these antibodies, we have identified conditions under which these sites are phosphorylated in cultured human cell lines. While phosphorylation of ATM was induced in response to a wide variety of DNA damage-inducing agents, phosphorylation of ATR was induced under a small subset of these conditions, most robustly with the...
Source: Molecular Cancer Research - Category: Cancer & Oncology Authors: Tags: DNA Damage Signaling: Poster Presentations - Proffered Abstracts Source Type: research