title: Regulation of the proapoptotic activity of huntingtin interacting protein 1 by Dyrk1 and caspase-3 in hippocampal neuroprogenitor cells.
abstract: Dual specific protein kinase Dyrks are thought to play a key role in the regulation of cell growth in a variety of cellular systems. Interestingly, human Dyrk1 is mapped to the Down's syndrome (DS) critical region on chromosome 21, and thought to be a candidate gene responsible for the mental retardation of DS patients. Huntingtin-interacting protein 1 (Hip-1), a proapoptotic mediator, is implicated as a molecular accomplice in the pathogenesis of Huntington's disease. In the present study we found that Dyrk1 selectively binds to and phosphorylates Hip-1 during the neuronal differentiation of embryonic hippocampal neuroprogenitor (H19-7) cells. The Dyrk1-mediated phosphorylation of Hip-1, in response to bFGF, resulted in the blockade of Hip-1-mediated neuronal cell death as well as the enhancement of neurite outgrowth. Furthermore, the addition of etoposide to proliferating H19-7 cells caused the diminished binding of Hip-1 to Dyrk1 and the levels of phosphorylated Hip-1 remarkably decreased. Simultaneously, the dissociated Hip-1 from Dyrk1 bound to caspase-3 in response to etoposide, which led to its activation and consequently cell death in H19-7 cells. These data suggest that the phosphorylation of Hip-1 by Dyrk1 has a dual role in regulating neuronal differentiation and cell death. The interaction between Dyrk1 and Hip-1 appeared to be differentially modulated by different kinds of stimuli, such as bFGF and etoposide in H19-7 cells.
authors.affiliation: Department of Biochemistry and Molecular Biology, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Jae Eun
authors.initials: JE
authors.lastname: Kang
authors.forename: Shin Ae
authors.initials: SA
authors.lastname: Choi
authors.forename: Jung Bum
authors.initials: JB
authors.lastname: Park
authors.forename: Kwang Chul
authors.initials: KC
authors.lastname: Chung
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D053148:Caspase 3; D020169:Caspases / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005047:Etoposide / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D011505:Protein-Tyrosine Kinases; D051381:Rats; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000097603:Dyrk Kinases
chemical_list: D053148:Caspase 3; D020169:Caspases; D004268:DNA-Binding Proteins; D005047:Etoposide; D019384:Nucleic Acid Synthesis Inhibitors; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D000097603:Dyrk Kinases; C073368:HIP1 protein, human; C505407:CASP3 protein, human; C505410:Casp3 protein, rat