Ku80 lysine crotonylation conversion to SUMOylation facilitates DNA non-homologous end joining and cellular resistance to radiation

ABSTRACT: A DNA double-strand break (DSB) is the most serious DNA damage and is also the principal molecular basis of radiotherapy. Upon DNA damage, the Ku80 is recruited and forms a critical DNA-PK complex at the DSB sites with Ku70 and the catalytic subunit (DNA-PKcs) to initiate DNA repair. How DNA-PK is assembled and activated is not fully understood. Based on the identification of radiation-reduced Ku80 K568 crotonylation through quantitative global lysine crotonylome analysis, we reveal that Ku80 K568 is crotonylated by p300-CBP-associated factor (PCAF). Upon DNA damage, the K568cr is decrotonylated by HDAC8. Decrotonylation of K568cr empties this site for the subsequent SUMOylation of Ku80 by CBX4.The conversion of Ku80 from K568 crotonylation to SUMOylation facilitates the assembly of DNA-PK complex and autophosphorylation of DNA-PKcs S2056, consequently activating the DSB repair. Moreover, mutation disrupting the post-translational modification (PTM) of Ku80 K568 site sensitizes cancer cells to radiotherapy in tumor-bearing nude mice models. Our findings provide fresh insights into the regulation of DNA-PK complex assembly and DSB repair. The conversion model between two different forms of post-translational modifications (PTMs) expands the atlas of therapeutic targets.

INSTRUMENT(S): timsTOF Pro 2

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: hongling zhao  

LAB HEAD: Pingkun Zhou

PROVIDER: PXD061039 | Pride | 2025-05-07

REPOSITORIES: Pride