Phosphoproteomics reveals novel modes of function and inter-relationships among PIKKs in response to genotoxic stress

ABSTRACT: The DNA damage response (DDR) is a complex signaling network that relies on cascades of protein phosphorylation, which are initiated by three protein kinases of the family of PI3-kinase-related protein kinases (PIKKs): ATM, ATR and DNA-PK. ATM is missing or inactivated in the genome instability syndrome, ataxia-telangiectasia (A-T). The relative shares of these PIKKs in the response to genotoxic stress and the functional relationships among them are central questions in the genome stability field. We conducted a comprehensive phosphoproteomic analysis in human wild-type and A-T cells treated with the double-strand break-inducing chemical, neocarzinostatin, and validated the results with the targeted proteomic technique, selected reaction monitoring. We also matched our results with 34 published screens for DDR factors, creating a valuable resource for identifying strong candidates for novel DDR players. We uncovered fine-tuned dynamics between the PIKKs following genotoxic stress, such as DNA-PK-dependent attenuation of ATM. In A-T cells, partial compensation for ATM absence was provided by ATR and DNA-PK, with distinct roles and kinetics. Our results highlight the intricate relationships between these PIKKs in regulating the DDR.

INSTRUMENT(S): QTRAP 5500

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Leukocyte, Cell Culture

SUBMITTER: Sapir Schlam  

LAB HEAD: Yosef Shiloh

PROVIDER: PXD020884 | Pride | 2020-11-25

REPOSITORIES: Pride