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 is robustly mobilized by double-strand breaks (DSBs) in the DNA. This network relies on extensive cascades of protein phosphorylation and dephosphorylation, which are initiated by three apical protein kinases that belong to the family of PI3-kinase-related protein kinases (PIKKs): ATM, ATR and DNA-PK. Loss of ATM leads to a prototypic 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 DSB-inducing chemical, neocarzinostatin, and validated the results with the targeted proteomic technique selected reaction monitoring (SRM). We uncovered redundant as well as non-redundant roles of the PIKKs following genotoxic stress and obtained evidence of a DNA-PK-dependent attenuation of the ATM response. In A-T cells, partial compensation for ATM absence was provided by ATR and DNA-PK, with distinct roles and kinetics to each of them. Our results shed light on the intricate relationships between the three PIKKs in regulating the DDR.

INSTRUMENT(S): LTQ Orbitrap Elite

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Leukocyte, Blood

DISEASE(S): Ataxia Telangiectasia

SUBMITTER: Sapir Schlam  

LAB HEAD: Yosef Shiloh

PROVIDER: PXD015455 | Pride | 2020-11-25

REPOSITORIES: Pride