PCNA-dependent accumulation of CDKN1A into nuclear foci after ionizing irradiation

► We report on the mechanisms of CDKN1A re-localization into nuclear foci in response to radiation and oxidative DNA damage. ► The accumulation of CDKN1A into nuclear foci after ionizing radiation is dependent on its direct physical interaction with PCNA. ► The direct interaction of CDKN1A and PCNA is facilitated by the de-phosphorylation of CDKN1A after exposure to ionizing radiation. ► Detailed dynamic measurements by live-cell imaging analysis reveal slightly delayed recruitment of CDKN1A compared to PCNA. ► The accumulation of CDKN1A into nuclear foci after ionizing radiation is distinct from CDKN1A's role in nucleotide excision repair and unrelated to double-strand break repair.