This gene encodes a member of the Dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) family. This member contains a nuclear targeting signal sequence, a protein kinase domain, a leucine zipper motif, and a highly conservative 13-consecutive-histidine repeat. It catalyzes its autophosphorylation on serine/threonine and tyrosine residues. It may play a significant role in a signaling pathway regulating cell proliferation and may be involved in brain development. This gene is a homolog of Drosophila mnb (minibrain) gene and rat Dyrk gene. It is localized in the Down syndrome critical region of chromosome 21, and is considered to be a strong candidate gene for learning defects associated with Down syndrome. Alternative splicing of this gene generates several transcript variants differing from each other either in the 5 UTR or in the 3 coalternative products:Additional isoforms seem to exist,catalytic activity:ATP + a protein = ADP + a phosphoprotein.,developmental stage:Expressed in the developing central nervous system.,disease:Overexpressed 1.5-fold in fetal Down syndrome brain.,enzyme regulation:Inhibited by RANBP9.,function:May play a role in a signaling pathway regulating nuclear functions of cell proliferation. Phosphorylates serine, threonine and tyrosine residues in its sequence and in exogenous substrates.,PTM:Autophosphorylated on tyrosine residues.,similarity:Belongs to the protein kinase superfamily. CMGC Ser/Thr protein kinase family. MNB/DYRK subfamily.,similarity:Contains 1 protein kinase domain.,subunit:Interacts RAD54L2/ARIP4 (By similarity). Interacts with RANBP9.,tissue specificity:Ubiquitous. Highest levels in skeletal muscle, testis, fetal lung and fetal kidney.,
