DNA and Chromosomes
Common motifs in ETAA1 and TOPBP1 required for ATR kinase activationDNA damage response Ser/Thr kinases, including ataxia telangiectasia-mutated (ATM) and Rad3-related (ATR), control cell cycle progression, DNA repair, and apoptosis. ATR is activated by ETAA1 activator of ATR kinase (ETAA1) or DNA topoisomerase II binding protein 1 (TOPBP1). Both ETAA1 and TOPBP1 contain experimentally defined ATR activation domains (AADs) that are mostly unstructured and have minimal sequence similarity. A tryptophan residue in both AADs is required for ATR activation, but the other features of these domains and the mechanism by which they activate ATR are unknown.
Evidence That G-quadruplex DNA Accumulates in the Cytoplasm and Participates in Stress Granule Assembly in Response to Oxidative StressCells engage numerous signaling pathways in response to oxidative stress that together repair macromolecular damage or direct the cell toward apoptosis. As a result of DNA damage, mitochondrial DNA or nuclear DNA has been shown to enter the cytoplasm where it binds to “DNA sensors,” which in turn initiate signaling cascades. Here we report data that support a novel signaling pathway in response to oxidative stress mediated by specific guanine-rich sequences that can fold into G-quadruplex DNA (G4DNA).