A wide-ranging cellular response to UV damage of DNA

Area of Science:

• Molecular Biology
• Cellular Signaling
• Proteomics

Background:

• The kinases ATM (Ataxia-Telangiectasia Mutated) and ATR (Ataxia-Telangiectasia and Rad3-Related) are critical regulators of the DNA damage response (DDR).
• These kinases orchestrate cell cycle progression and DNA repair pathways through protein phosphorylation.
• Previous understanding of DDR signaling pathways was limited in scope.

Purpose of the Study:

• To comprehensively identify ATM/ATR kinase substrates phosphorylated upon UV-induced DNA damage.
• To expand the known repertoire of proteins involved in DNA damage signaling.
• To demonstrate the utility of the PhosphoScan proteomic method for serine/threonine phosphorylation site discovery.

Main Methods:

• Large-scale proteomic analysis using the PhosphoScan method.
• Induction of DNA damage via UV irradiation in cellular models.
• Mass spectrometry-based identification of phosphorylated serine and threonine residues.

Main Results:

• Identified 231 novel phosphorylation sites induced by UV DNA damage or dependent on ATR.
• Expanded the known protein substrate network of ATM/ATR kinases.
• Discovered phosphorylation sites in proteins not previously associated with DNA damage signaling.

Conclusions:

• The DNA damage response impacts a wider array of cellular processes than previously recognized.
• The study provides a foundational dataset for understanding ATM/ATR signaling in DNA repair.
• The PhosphoScan method is a versatile tool for mapping signaling pathways in various diseases.