title: Nuclear import of Nkx2-2 is mediated by multiple pathways.
abstract: Nkx2-2 homeoprotein is essential for the development of the central nervous system and pancreas. Although the nuclear localization signals of Nkx2-2 have been identified, the responsible transport receptor is still unknown. Here, we demonstrate that imp α1 not only interacts with Nkx2-2 but also transports it into the nucleus in vitro by acting together with imp β1. However, the nuclear import of Nkx2-2 in cells was not inhibited in response to knockdown expression of endogenous imp β1 or over-expression of Bimax2. Furthermore, imp β1 and imp 13, but not imp 4, directly interact with Nkx2-2 and are capable of transporting Nkx2-2 in an in vitro import assay. By GST pull-down assay, we demonstrate that mutation of NLS1 or NLS2 has no effect on interaction with imp α1 or imp 13, but significantly reduced binding to imp β1. Thus, the nuclear import of Nkx2-2 is mediated not only by the classical import pathway but also directly by imp β1 or imp 13.
authors.affiliation: Xiamen University School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China.
authors.forename: Wenbo
authors.initials: W
authors.lastname: Lin
authors.affiliation: Xiamen University School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China.
authors.forename: PengPeng
authors.initials: P
authors.lastname: Xu
authors.affiliation: Xiamen University School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China.
authors.forename: YingYing
authors.initials: Y
authors.lastname: Guo
authors.affiliation: Xiamen University School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China.
authors.forename: Qingjie
authors.initials: Q
authors.lastname: Jia
authors.affiliation: Xiamen University School of Life Sciences, Xiamen University, Xiamen, Fujian, 361005, China. Electronic address: taotao@xmu.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Tao
mesh_terms: D021581:Active Transport, Cell Nucleus; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D005786:Gene Expression Regulation; D005982:Glutathione Transferase / Q000378:metabolism; D057809:HEK293 Cells; D006367:HeLa Cells; D000090322:Homeobox Protein Nkx-2.2; D018398:Homeodomain Proteins / Q000378:metabolism*; D006801:Humans; D028884:Karyopherins / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D009154:Mutation; D041681:NIH 3T3 Cells; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D029961:Zebrafish Proteins; D028961:beta Karyopherins
chemical_list: D000090322:Homeobox Protein Nkx-2.2; D018398:Homeodomain Proteins; C527880:IPO13 protein, human; C424166:KPNB1 protein, human; D028884:Karyopherins; C000715631:NKX2-2 protein, human; C000715627:Nkx2-2 protein, mouse; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D014157:Transcription Factors; D029961:Zebrafish Proteins; D028961:beta Karyopherins; C514744:importin 13 protein, mouse; C000715630:nkx2.2b protein, zebrafish; D005982:Glutathione Transferase; D010744:Phosphoric Monoester Hydrolases; C021822:myo-inositol-1 (or 4)-monophosphatase
keywords: Homeodomain; Importin α; Importin β; Nkx2-2; Nuclear localization signal