2000 Fiscal Year Annual Research Report

細胞質から核への蛋白質輸送の分子機構:その多様性とエネルギー要求性

Research Project

Project/Area Number	11237202
Research Institution	Osaka University
Principal Investigator	米田悦啓大阪大学, 医学系研究科, 教授 (80191667)
Co-Investigator(Kenkyū-buntansha)	原口徳子郵政省通信総合研究所, 関西先端研究センター・生物情報研究室, 主任研究員
Keywords	核蛋白質輸送 / β-catenin / importin / Ran / 核膜孔 / exportin / レプトマイシンB / 転写因子
Research Abstract	細胞種特異的な細胞内情報網を解明する目的で、calcium/calmodulin-dependent protein kinase IV(CaM kinase IV)に着目して、その輸送機構の解明を進めた。セミインタクト細胞を用いたin vitro系において、エールリッヒ腹水癌細胞抽出液中にもマウス小脳抽出液中にもCaM kinase IVを輸送する因子が含まれていることがわかったが、それぞれの因子は異なる可能性が示唆され、CaM kinase IVは複数の細胞種特異的経路によって輸送されていることが考えられる。一方、蛋白質の核膜孔通過のステップを解明するため、それ自身単独で通過可能な分子であるimportin βを指標にし、その点変異体を複数構築して、それぞれの核膜孔通過能を解析したところ、核膜孔の出入りに関わる重要な配列の存在を示唆する結果が得られた。また、核-細胞質間情報交換の多様性を明らかにする目的で,β-cateninに着目した。β-cateninは、importin βと同様に、それ自身単独でRan非依存的に核内に移行することがわかり、その移行には、β-cateninが持つ12回のアルマジロ反復配列のうち、N末端側から数えて10-12番目の領域が重要な役割を果たし、その部分で核膜孔複合体構成因子と結合することが明らかとなった。さらに、β-cateninは、核内で協調して働く転写因子であるLef-1を細胞質から核へ輸送する能力を持っていることを証明した。この結果は、β-cateninが、ある種の転写因子のco-activatorとして機能するだけでなく、その輸送因子としても機能しうることを初めて明らかにしたもので、β-cateninを中心とした細胞内情報伝達系に全く新しい知見を示すことができた。一方、β-cateninは、核から細胞質に輸送されることも明らかとなったが、その輸送はレプトマイシンBによって阻害されないことから、これまでに知られている核外輸送因子であるexportin以外の因子の関与が推測され、現在、この因子の同定を進めている。

Research Products
(15 results)

All Other

All Publications (15 results)

[Publications] Haraguchi,T.: "Live fluorescence imaging reveals early recruitment of emerin, LBR, HP1β and RanBP2 to reforming functional nuclear envelope."J.Cell Sci.. 113. 779-794 (2000)
[Publications] Matsubae,M.: "Characterization of the nuclear transport of a novel leucine-rich acidic nuclear protein-like protein."FEBS Lett.. 468. 171-175 (2000)
[Publications] Tachibana,T.: "Recycling of importin α from the nucleus is suppressed by loss of RC1 function in living mammalian cells."Cell Struct.Funct.. 25. 95-103 (2000)
[Publications] Ikuta,T.: "Nucleocytoplasmic shuttling of the aryl hydrocarbon receptor."J.Biochem.. 127. 503-509 (2000)
[Publications] Tanabe,K.: "The small GTP-binding protein TC10 promotes growth cone formation and nerve elongation in neuronal cells, and its transcription is induced during nerve regeneration in rat."J.Neurosci.. 20. 4138-4144 (2000)
[Publications] Takeda,K.: "Characterization of human herpesvirus 7 U27 gene product and identification of its nuclear localization signal."Virol.. 272. 394-401 (2000)
[Publications] Lee,S.J.: "The adoption of a twisted structure of importin-β is essential for the protein-protein interaction required for unclear transport."J.Mol.Biol.. 302. 251-264 (2000)
[Publications] Sueishi,M.: "The FHA domain of Ki-67 antigen interacts with a novel kinesin-like protein Hklp2."J.Biol.Chem.. 275. 28888-28892 (2000)
[Publications] Yoneda,Y.: "Nucleocytoplasmic protein traffic and its significance to cell function."Genes Cells. 5. 777-787 (2000)
[Publications] Yoneda,Y.: "New steps toward the nucleocytoplasmic traffic of macromolecules."Cell Struct.Funct.. 25. 241-242 (2000)
[Publications] Shimizu,S.: "Essential role of voltage-dependent anion channel in various forms of apoptosis in mammalian cells."J.Cell Biol.. 152. 237-250 (2001)
[Publications] Nagoshi,E.: "Dimerization of the sterol regulatory element-binding protein-2 via the helix-loop-helix-leucine zipper domain is prerequisite for its nuclear localization mediated by importin β."Mol.Cell.Biol.. (in press). (2001)
[Publications] Akakura,S.: "A role for Hsc70 in regulating nucleo-cytoplasmic transport of a temperature-sensitive p53 (p53Val135)."J.Biol.Chem.. (in press). (2001)
[Publications] Kurisaki,a.: "Transforming growth factor-β induces nuclear import of Smad3 in an importin-β1 and Ran-dependent manner."Mol.Biol.Cell. (in press). (2001)
[Publications] Hieda,M.: "Nuclear import of the U1A splicesome protein is mediated by importin α/β and Ran in living mammalian cells."J.Biol.Chem.. (in press). (2001)

2000 Fiscal Year Annual Research Report

細胞質から核への蛋白質輸送の分子機構:その多様性とエネルギー要求性

Principal Investigator

米田 悦啓 大阪大学, 医学系研究科, 教授 (80191667)

Research Products

[Publications] Haraguchi,T.: "Live fluorescence imaging reveals early recruitment of emerin, LBR, HP1β and RanBP2 to reforming functional nuclear envelope."J.Cell Sci.. 113. 779-794 (2000)

[Publications] Matsubae,M.: "Characterization of the nuclear transport of a novel leucine-rich acidic nuclear protein-like protein."FEBS Lett.. 468. 171-175 (2000)

[Publications] Tachibana,T.: "Recycling of importin α from the nucleus is suppressed by loss of RC1 function in living mammalian cells."Cell Struct.Funct.. 25. 95-103 (2000)

[Publications] Ikuta,T.: "Nucleocytoplasmic shuttling of the aryl hydrocarbon receptor."J.Biochem.. 127. 503-509 (2000)

[Publications] Tanabe,K.: "The small GTP-binding protein TC10 promotes growth cone formation and nerve elongation in neuronal cells, and its transcription is induced during nerve regeneration in rat."J.Neurosci.. 20. 4138-4144 (2000)

[Publications] Takeda,K.: "Characterization of human herpesvirus 7 U27 gene product and identification of its nuclear localization signal."Virol.. 272. 394-401 (2000)

[Publications] Lee,S.J.: "The adoption of a twisted structure of importin-β is essential for the protein-protein interaction required for unclear transport."J.Mol.Biol.. 302. 251-264 (2000)

[Publications] Sueishi,M.: "The FHA domain of Ki-67 antigen interacts with a novel kinesin-like protein Hklp2."J.Biol.Chem.. 275. 28888-28892 (2000)

[Publications] Yoneda,Y.: "Nucleocytoplasmic protein traffic and its significance to cell function."Genes Cells. 5. 777-787 (2000)

[Publications] Yoneda,Y.: "New steps toward the nucleocytoplasmic traffic of macromolecules."Cell Struct.Funct.. 25. 241-242 (2000)

[Publications] Shimizu,S.: "Essential role of voltage-dependent anion channel in various forms of apoptosis in mammalian cells."J.Cell Biol.. 152. 237-250 (2001)

[Publications] Nagoshi,E.: "Dimerization of the sterol regulatory element-binding protein-2 via the helix-loop-helix-leucine zipper domain is prerequisite for its nuclear localization mediated by importin β."Mol.Cell.Biol.. (in press). (2001)

[Publications] Akakura,S.: "A role for Hsc70 in regulating nucleo-cytoplasmic transport of a temperature-sensitive p53 (p53Val135)."J.Biol.Chem.. (in press). (2001)

[Publications] Kurisaki,a.: "Transforming growth factor-β induces nuclear import of Smad3 in an importin-β1 and Ran-dependent manner."Mol.Biol.Cell. (in press). (2001)

[Publications] Hieda,M.: "Nuclear import of the U1A splicesome protein is mediated by importin α/β and Ran in living mammalian cells."J.Biol.Chem.. (in press). (2001)

米田悦啓大阪大学, 医学系研究科, 教授 (80191667)