Dual-specificity kinase which possesses both serine/threonine and tyrosine kinase activities (PubMed:18938227). Plays an important role in double-strand breaks (DSBs) repair following DNA damage. Mechanistically, phosphorylates RNF169 and increases its ability to block accumulation of TP53BP1 at the DSB sites thereby promoting homologous recombination repair (HRR) (By similarity). May play a role in a signaling pathway regulating nuclear functions of cell proliferation. Modulates alternative splicing by phosphorylating the splice factor SRSF6 (By similarity). Exhibits a substrate preference for proline at position P+1 and arginine at position P-3. Has pro-survival function and negatively regulates the apoptotic process. Promotes cell survival upon genotoxic stress through phosphorylation of SIRT1. This in turn inhibits TP53 activity and apoptosis (By similarity). Phosphorylates SEPTIN4, SEPTIN5 and SF3B1 at 'Thr-434' (PubMed:18938227). ATP + L-seryl-[protein] = ADP + H(+) + O-phospho-L-seryl-[protein] ATP + L-threonyl-[protein] = ADP + H(+) + O-phospho-L-threonyl-[protein] ATP + L-tyrosyl-[protein] = ADP + H(+) + O-phospho-L-tyrosyl-[protein] Inhibited by RANBP9 (By similarity). Inhibited by harmine, leucettamine B and leucettine L41 (PubMed:22998443). Interacts with RANBP9. Interacts with RAD54L2/ARIP4. Interacts with CRY2 (By similarity). Interacts with WDR68 (By similarity). Interacts with SRSF6 (PubMed:22767602). Interacts with SIRT1 (By similarity). Interacts with SEPTIN4 and SEPTIN5 (PubMed:18938227). Detected in brain (at protein level). Ubiquitous. The polyhistidine repeats act as targeting signals to nuclear speckles. Can also autophosphorylate on serine and threonine residues (in vitro) (By similarity). Autophosphorylated on numerous tyrosine residues (PubMed:8631952). Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MNB/DYRK subfamily.