title: A novel DYRK1B inhibitor AZ191 demonstrates that DYRK1B acts independently of GSK3β to phosphorylate cyclin D1 at Thr(286), not Thr(288).
abstract: DYRK1B (dual-specificity tyrosine phosphorylation-regulated kinase 1B) is amplified in certain cancers and may be an oncogene; however, our knowledge of DYRK1B has been limited by the lack of selective inhibitors. In the present study we describe AZ191, a potent small molecule inhibitor that selectively inhibits DYRK1B in vitro and in cells. CCND1 (cyclin D1), a key regulator of the mammalian G1-S-phase transition, is phosphorylated on Thr(286) by GSK3β (glycogen synthase kinase 3β) to promote its degradation. DYRK1B has also been proposed to promote CCND1 turnover, but was reported to phosphorylate Thr(288) rather than Thr(286). Using in vitro kinase assays, phospho-specific immunoblot analysis and MS in conjunction with AZ191 we now show that DYRK1B phosphorylates CCND1 at Thr(286), not Thr(288), in vitro and in cells. In HEK (human embryonic kidney)-293 and PANC-1 cells (which exhibit DYRK1B amplification) DYRK1B drives Thr(286) phosphorylation and proteasome-dependent turnover of CCND1 and this is abolished by AZ191 or DYRK1B RNAi, but not by GSK3β inhibitors or GSK3β RNAi. DYRK1B expression causes a G1-phase cell-cycle arrest, but overexpression of CCND1 (wild-type or T286A) fails to overcome this; indeed, DYRK1B also promotes the expression of p21CIP1 (21 kDa CDK-interacting protein 1) and p27KIP1 (CDK-inhibitory protein 1). The results of the present study demonstrate for the first time that DYRK1B is a novel Thr(286)-CCND1 kinase that acts independently of GSK3β to promote CCND1 degradation. Furthermore, we anticipate that AZ191 may prove useful in defining further substrates and biological functions of DYRK1B.
authors.affiliation: *Signalling Programme, The Babraham Institute, Babraham Research Campus, Cambridge, CB22 3AT, U.K.
authors.forename: Anne L
authors.initials: AL
authors.lastname: Ashford
authors.forename: David
authors.initials: D
authors.lastname: Oxley
authors.forename: Jason
authors.initials: J
authors.lastname: Kettle
authors.forename: Kevin
authors.initials: K
authors.lastname: Hudson
authors.forename: Sylvie
authors.initials: S
authors.lastname: Guichard
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Cook
authors.forename: Pamela A
authors.initials: PA
authors.lastname: Lochhead
mesh_terms: D002478:Cells, Cultured; D019938:Cyclin D1 / Q000737:chemistry / Q000378:metabolism*; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D038362:Glycogen Synthase Kinase 3 / Q000502:physiology*; D000071679:Glycogen Synthase Kinase 3 beta; D057809:HEK293 Cells; D006574:Heterocyclic Compounds, 2-Ring / Q000494:pharmacology*; D006801:Humans; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D047428:Protein Kinase Inhibitors / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*; D059748:Proteolysis; D011743:Pyrimidines / Q000494:pharmacology*; D013379:Substrate Specificity; D013912:Threonine / Q000378:metabolism*; D000097603:Dyrk Kinases
chemical_list: D019938:Cyclin D1; D038362:Glycogen Synthase Kinase 3; D000071679:Glycogen Synthase Kinase 3 beta; D006574:Heterocyclic Compounds, 2-Ring; D047428:Protein Kinase Inhibitors; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D011743:Pyrimidines; D013912:Threonine; D000097603:Dyrk Kinases; C586752:AZ191 compound; C000605506:GSK3B protein, human