Interactome Profiling of DNA Damage Response (DDR) Mediators with Immunoprecipitation-Mass Spectrometry.

Immunoprecipitation-mass spectrometry (IP-MS) is a versatile tool to probe for global protein-protein interactions (PPIs) in biological samples. Such interactions coordinate complex biological processes, such as the DNA damage response (DDR). Induction of DNA damage activates signaling networks where posttranslational modifications cause PPI that facilitate DNA repair and cell cycle coordination. Protein interactome profiling of DDR sensors, transducers, and effectors has the potential to identify novel DDR mechanisms that could advance our understanding and treatment of diseases associated with DDR defects, such as cancer. The protocol described here is a routine PPI analysis procedure that can be performed on samples stimulated with DNA damage. All processes and reagents are optimized for maximum sensitivity on the interactome and minimal contamination for the mass spectrometer.