Might affect PCNA interaction with some CDK (cell division protein kinase) complexes; stimulates DNA excision repair in vitro and inhibits entry of cells into S phase. In T-cells, functions as a regulator of p38 MAPKs by inhibiting p88 phosphorylation and activity (By similarity). Interacts with AURKA, PCNA, GADD45GIP1 and MAPK14. By UV radiation, X-rays, growth arrest and alkylating agents. The induction is mediate by some kinase(s) other than PKC. Belongs to the GADD45 family.