Dual-specificity kinase which possesses both serine/threonine and tyrosine kinase activities (PubMed:12633499). Plays an essential role in ribosomal DNA (rDNA) double-strand break repair and rDNA copy number maintenance. During DNA damage, mediates transcription silencing in part via phosphorylating and enforcing DSB accumulation of the histone methyltransferase EHMT2. Enhances the transcriptional activity of TCF1/HNF1A and FOXO1. Inhibits epithelial cell migration. Mediates colon carcinoma cell survival in mitogen-poor environments. Inhibits the SHH and WNT1 pathways, thereby enhancing adipogenesis. In addition, promotes expression of the gluconeogenic enzyme glucose-6-phosphatase catalytic subunit 1 (G6PC1). 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. Dimer. Interacts with DCOHM, MAP2K3/MKK3, RANBP9 and TCF1/HNF1A. Part of a complex consisting of RANBP9, RAN, DYRK1B and COPS5. Interacts with DCAF7. Interacts with RNF169. Localizes to sites of double-strand breaks (DSBs) following DNA damage. Isoform 1 and isoform 2 are broadly expressed. Isoform 3 seems specific for skeletal muscle (at protein level). Isoform 1 is present from 14 dpc. Isoform 3 is present from 18 dpc (at protein level). Phosphorylated by MAP kinase. Tyrosine phosphorylation may be required for dimerization (By similarity). Inactive. Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MNB/DYRK subfamily.