Phosphorylation of TRF2 promotes its interaction with TIN2 and regulates DNA repair at damaged telomeres

ABSTRACT: Protein phosphatase magnesium-dependent 1 delta (PPM1D) is involved in termination of the cell cycle checkpoint by counteracting activity of the tumour suppressor protein p53. By dephosphorylating various proteins at chromatin, PPM1D contributes to the control of DNA damage response and DNA repair. Using proximity biotinylation followed by proteomic analysis, we identified interaction between PPM1D and the components of the shelterin complex that protects telomeric DNA. Interaction between PPM1D and TRF2 was confirmed by immunoprecipitation and proximity ligation assay. Confocal microscopy revealed colocalisation of the endogenous PPM1D with TRF2 at telomeres. Further, we found that TRF2 was phosphorylated by ATR at S410 after induction of DNA damage at telomeres and this modification was increased in cells lacking PPM1D or after PPM1D inhibition. Phosphorylation of TRF2 stimulated its interaction with TIN2 at telomeres and in vitro. Conversely, overexpression of PPM1D impaired localisation of TIN2 at telomeres. Finally, inhibition of PPM1D impaired recruitment of 53BP1 and RAD51 to DNA double strand breaks at telomeres. Expression of TRF2-S410A mutant fully rescued the recruitment of 53BP1 to telomeric breaks. These results suggest that TRF2 phosphorylation promotes association of TIN2 with the shelterin complex and regulates DNA repair at telomeres.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Pavel Talacko  

LAB HEAD: Libor Macurek

PROVIDER: PXD035268 | Pride | 2023-03-11

REPOSITORIES: Pride