HIPK2, a nuclear serine/threonine kinase similar to the MNB/DYRK type protein kinases, represses transcription mediated by homeodomain containing transcription factors. HIPK2 is activated by ultraviolet (UV) radiation and selectively phosphorylates p53 to promote p53-dependent gene expression. HIPK2 interacts with various proteins, including members of the p53 family, to regulate cell cycle and apoptosis. Variants of HIPK2 have been observed due to alternative splicing.Synonyms: Homeodomain-interacting protein kinase 2