title: Unusual function of the activation loop in the protein kinase DYRK1A.
abstract: Protein kinases of the DYRK (dual-specificity tyrosine phosphorylation-regulated kinase) family require phosphorylation of a conserved tyrosine residue in the activation loop for full activity. Here we have characterized the role of conserved amino acids that are located in the vicinity of the phosphorylated tyrosine in DYRK1A (Tyr-321). Mutation of Gln-323, but not Asn-365 or Glu-366, to either alanine, glutamate, or asparagine reduced the in vitro-kinase activity of DYRK1A towards the peptide substrate, DYRKtide, to a similar degree (15-37% of wild type) as the mutation of the phosphorylation site itself (Y321F). Similarly, the in vivo-kinase activity of DYRK1A-Q323N and of DYRK1A-Y321F, as assessed by Ser-727 phosphorylation of signal transducer and activator of transcription 3 (STAT3) in COS-7 cells, was markedly reduced in comparison with wild type DYRK1A. These data show that the contribution of Gln-323 and Tyr-321 to the full catalytic activity of DYRK1A is a specific functional characteristic of the DYRK family.
authors.affiliation: Institut für Pharmakologie und Toxikologie, RWTH Aachen, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Wiechmann
authors.forename: Hanna
authors.initials: H
authors.lastname: Czajkowska
authors.forename: Katrin
authors.initials: K
authors.lastname: de Graaf
authors.forename: Joachim
authors.initials: J
authors.lastname: Grötzinger
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Joost
authors.forename: Walter
authors.initials: W
authors.lastname: Becker
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017354:Point Mutation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D017433:Protein Structure, Secondary; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D011994:Recombinant Proteins / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D000097603:Dyrk Kinases
chemical_list: D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011994:Recombinant Proteins; D000097603:Dyrk Kinases