title: Nuclear translocation of doublecortin-like protein kinase and phosphorylation of a transcription factor JDP2.
abstract: Doublecortin-like protein kinase (DCLK) is a microtubule-associated protein kinase predominantly expressed in brain. In a previous paper, we reported that zebrafish DCLK2 (zDCLK) was cleaved into two functional fragments; the N-terminal zDCLK(DC+SP) with microtubule-binding activity and the C-terminal zDCLK(kinase) with a Ser/Thr protein kinase activity. In this study, we demonstrated that zDCLK(kinase) was widely distributed in the cytoplasm and translocated into the nucleus when the cells were treated under hyperosmotic conditions with NaCl or mannitol. By two-hybrid screening using the C-terminal domain of DCLK, Jun dimerization protein 2 (JDP2), a nuclear transcription factor, was identified as zDCLK(kinase)-binding protein. Furthermore, JDP2 served as an efficient substrate for zDCLK(kinase) only when histone was present. These results suggest that the kinase fragment of DCLK is translocated into the nucleus upon hyperosmotic stresses and that the kinase efficiently phosphorylates JDP2, a possible target in the nucleus, with the aid of histones.
authors.affiliation: Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Nagamine
authors.affiliation: Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan.
authors.forename: Shohgo
authors.initials: S
authors.lastname: Nomada
authors.affiliation: Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Onouchi
authors.affiliation: Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan.
authors.forename: Isamu
authors.initials: I
authors.lastname: Kameshita
authors.affiliation: Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa 761-0795, Japan. Electronic address: sueyoshi@ag.kagawa-u.ac.jp.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Sueyoshi
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D000089742:Doublecortin-Like Kinases; D006657:Histones / Q000378:metabolism; D009997:Osmotic Pressure; D010766:Phosphorylation; D054730:Protein Interaction Domains and Motifs; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D020798:Two-Hybrid System Techniques; D029961:Zebrafish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D006657:Histones; D011994:Recombinant Proteins; D012097:Repressor Proteins; D029961:Zebrafish Proteins; D000089742:Doublecortin-Like Kinases; C521839:DCLK protein, zebrafish; D017346:Protein Serine-Threonine Kinases
keywords: Doublecortin; Doublecortin-like protein kinase; Hyperosmotic stress; Jun dimerization protein-2; Nuclear translocation