我々は、世界に先駆け、インスリン受容体 cDNAを単離した(Cell, 1985. Ebina et al.)。そして、インスリン受容体のチロシンキナーゼ活性がインスリン作用発現に必須であることを証明し(Proc. Natl. Acad. Sci. USA, 1987)、受容体遺伝子上でチロシンキナーゼドメインが欠失している糖尿病患者を発見した(Science, 1989)。また、インスリンの「細胞内へのグルコース取り込み促進」作用には、PI 3-キナーゼの活性化が必須であることを世界に先駆けて報告した(BBRC, 1993., Proc. Natl. Acad. Sci. USA, 1995.)。さらにその下流のAkt2がこの作用発現に重要であることをRNAiの手法を用い明らかにした(J.Biol.Chem., 2003)。また、2型糖尿病発症には、“肝臓におけるインスリン作用不全”が重要であることを見出した(Nature Genetics, 1998)。インスリン作用の中で最も重要なものの1つが膜を12回貫通するGLUT4（Glucose Transporter Type 4;インスリン反応性グルコーストランスポーター）のトランスロケーションとその結果起こるグルコースの細胞内への取り込み促進である。我々は世界で初めて、GLUT4のトランスロケーションを定量的に測定する画期的な方法を考案した(J.Biol.Chem., 1993)。この新しい方法論により、GLUT4トランスロケーションには、PI3-キナーゼとAkt2の活性化が必須であること、GLUT4はインスリンによりのみ制御されると考えられていたが、三量体GタンパクのGqを活性化するような生理活性物質によってもおこることを発見した。(J.Biol.Chem.,1996, Diabetes 1998)。

我々は細胞増殖因子に共通なシグナル伝達因子であるPI 3-キナーゼがインスリンによるGLUT4のトランスロケーションに必須であること、そしてPDGFやEGFなどのPI 3-キナーゼを活性化する細胞増殖因子も培養細胞レベルではGLUT4のトランスロケーションを引き起こし、細胞内へのグルコースの取り込みを促進することを世界に先駆けて発見した(J.Biol.Chem., 1999)。しかし、インスリンと異なり、PDGF などを生体に投与しても血糖値は下がらない。その原因は骨格筋においてはインスリンレセプターは多く発現しているが、PDGFレセプターはほとんど発現していないためであり、PI 3-キナーゼ以後のGLUT4のトランスロケーションを引き起こすまでの細胞内シグナルは存在していると考えた。そこでトランスジェニックの手法で骨格筋で PDGFレセプターを特異的に発現しているトランスジェニックマウスを確立した。そしてPDGF、インスリンなどを投与して血糖値降下などの解析を行った。

その結果、このトランスジェニックマウスではインスリンと同様PDGF投与によって骨格筋へのグルコースの取り込みは明らかに促進したが、血糖値の低下は見られなかった(Diabetes 2004)。この事実はインスリンは骨格筋におけるグルコースの取り込み促進と共に、肝臓におけるグルコース放出抑制を非常に早期に同時に行う。従って、血糖値低下の原因は、骨格筋へのグルコース取り込み促進だけでなく、早期に起こる肝からのグルコース放出抑制も重要である事が明らかとなった。今後肝でのインスリン作用も血糖低下には重要である事が分かってきたので解明を進める。

最近、ヒトの血清中にはインスリン受容体のαサブユニット（インスリン結合ドメイン）が切断され、遊離している事を世界で初めて発見し、その測定のためのELISAキットを作製し、MBL社と共同で市販した。糖尿病患者では血中遊離αサブユニットが増量していることを見出した。また、糖尿病モデルマウスでも高血糖になると共に血中に多くのインスリン受容体αサブユニットが遊離されている事を確認した（Diabetes 2007）。この事実は糖尿病研究に全く新しい展開を与えるものである。徳島県が進めている糖尿病対策に協力すべく、本研究を強力に進めることが求められている。

業　績

1)        IRS1-Independent Defects Define Major Nodes of Insulin Resistance.   Kyle L. Hoehn, Cordula Hohnen-Behrens, Anna Cederberg, Lindsay E. Wu, Nigel Turner, Tomoyuki Yuasa, Yousuke Ebina, and David E. James.  Cell Metabolism, 7, 421-433, (07 May 2008)      IF:17.148

2)        Regulated motion of glycoproteins revealed by direct visualization of a single cargo in the endoplasmic reticulum.   Hisao Nagaya, Taku Tamura, Arisa Higa-Nishiyama, Koji Ohashi, Mayumi Takeuchi, Hitoshi Hashimoto, Kiyotaka Hatsuzawa, Masataka Kinjo, Tatsuya Okada, and Ikuo Wada.  J Cell Biol.;180(1):129-43. (14 Jan 2008)       IF:9.598

3)        Proteomic screen defines the Polo-box domain interactome and identifies Rock2 as a Plk1 substrate.   Drew M Lowery, Karl R Clauser, Majbrit Hjerrild, Dan Lim, Jes Alexander, Kazuhiro Kishi, Shao-En Ong, Steen Gammeltoft, Steven A Carr and Michael B Yaffe.  The EMBO Journal 26, 2262?2273, (02 May 2007)   IF:8.662

4)        Deficiency of Cbl-b gene enhances infiltration and activation of macrophages in adipose tissue and causes peripheral insulin resistance in mice.   Katsuya Hirasaka, Shohei Kohno, Jumpei Goto, Harumi Furochi, Kazuaki Mawatari, Nagakatsu Harada, Toshio Hosaka, Yutaka Nakaya, Kazumi Ishidoh, Toshiyuki Obata, Yousuke Ebina, Hua Gu, Shin’ichi Takeda, Kyoichi Kishi and Takeshi Nikawa.  Diabetes., 56(10):2511-2522. (Oct 2007)              IF:8.261

5)        Soluble insulin receptor ectodomain is elevated in the plasma of patients with diabetes mellitus.   Toshiyuki Obata, Ichiro Yokota, Kazuhiro Yokoyama, Eiji Okamoto, Yoshiko Kanezaki, Yoshinori Tanaka, Hiroshi Maegawa, Kiyoshi Teshigawara, Fumiko Hirota, Tomoyuki Yuasa, Kazuhiro Kishi, Atsushi Hattori, Seiichi Hashida, Kazuhiko Masuda, Mitsuru Matsumoto, Toshio Matsumoto, Atsunori Kashiwagi, and Yousuke Ebina  Diabetes., 56(8):2028-2035. (2007)               IF:8.261

6)        APS-mediated Ubiquitination of the Insulin Receptor Enhances its Internalization, but does not Induce its Degradation   Kazuhiro Kishi, Kazuaki Mawatari, Kikuko Sakai-Wakamatsu, Tomoyuki Yuasa, Miao Wang, Makoto Ogura-Sawa, Yutaka Nakaya, Shigetsugu Hatakeyama and  Yousuke Ebina  Endocrine J., 54(1):77-88. (Feb 2007)    IF:1.572

7)        Angiotensin II inhibits insulin-induced actin stress fiber formation and glucose uptake via ERK1/2   Hossein Nazari, Akira Takahashi, Nagakatsu Harada, Kazuaki Mawatari, Masayuki Nakano, Kazuhiro Kishi, Yousuke Ebina and Yutaka Nakaya  The Journal of Medical Investigation, 54(1,2):19-27. (Feb 2007)   IF:0

8)        Intra-islet insulin suppresses glucagon release via GABA-GABA(A) receptor system.   Elaine Xu, Mohan Kumar, Yi Zhang, William Ju, Toshiyuki Obata T, Nina Zhang, Shiying Liu, Anna Wendt, Shaoping Deng, Yousuke Ebina, Michael B.Wheeler, Matthias Braun, Qinghua Wang  Cell Metabolism. 3(1): 47-58. (Jan 2006)    IF: 17.148

9)        Functional Analysis of PIK3CA Gene Mutations in Human Colorectal Cancer   Tsuneo Ikenoue, Fumihiko Kanai1, Yohko Hikiba, Toshiyuki Obata, Yasuo Tanaka, Jun Imamura, Miki Ohta, Jazag Amarsana, Bayasi Guleng, Keisuke Tateishi, Yoshinari Asaoka, Masayuki Matsumura, Takao Kawabe and Masao Omata  Cancer Research; 65(11):4562-7.  (Jun 2005)     IF:8.649

10)     ERK1/2 activation by angiotensin II inhibits insulin-induced glucose uptake in vascular smooth muscle cells   Yuki Izawa, Masanori Yoshizumi, Yoshiko Fujita, Nermin Ali, Yasuhisa Kanematsu, Keisuke Ishizawa, Koichiro Tsuchiya, Toshiyuki Obata, Yousuke Ebina and Shuhei Tomita  Experimental Cell Research; 308(2): 291-9.  (15 Aug 2005)     IF:3.949

11)     Platelet-derived growth factor stimulates glucose transport in skeletal muscles of transgenic mice specifically expressing PDGF receptor in the muscle, but does not affect blood glucose levels   Tomoyuki Yuasa, Rei Kakuhata, Kazuhiro Kishi, Toshiyuki Obata, Yasuo Shinohara, Yoshimi Bando, Keisuke Izumi, Fumiko Kajiura, Mitsuru Matsumoto and Yousuke Ebina  Diabetes 53, 2776-2786 (Nov 2004)    IF:8.298

12)     Protein Phosphatase 2A negatively Regulates insulin's Metabolic Signaling Pathway by Inhibiting Akt (Protein Kinase B) Activity in 3T3-L1 Adipocytes   Satoshi Ugi, Takeshi Imamura, Hiroshi Maegawa, Katsuya Egawa, Takeshi Yoshizaki, Kun Shi, Toshiyuki Obata, Yousuke Ebina, Atsunori Kashiwagi and Jerrold M. Olefsky  Mol. Cell. Biol. 241(19) 8778-8789 (Oct 2004)           IF:8.142

13)     KATP Channel Knockout Mice with transgenic Mice Expressing a Dominant-Negative Form of Human Insulin receptor have Glucose Intolerance but not Diabetes   Yoshiko Kanezaki, Toshiyuki Obata, Rie Matsushima, Asako Minami, Tomoyuki Yuasa, Kazuhiro Kishi, Yoshimi Bando, Hisanori Uehara, Keisuke Izumi, Tasuku Mitani, Mitsuru Matsumoto, Yukari Takeshita, Yutaka Nakaya, Toshio Matsumoto and Yousuke Ebina  Endocrine J. 51(2) 133-144 (Apr 2004)               IF:1.045

14)     ZFH4 protein is expressed in many neurons of developing rat brain.   Shigeharu Nogami, Yoko Ishii, Makoto Kawaguchi, Nobuo Sakata, Takeshi Oya, Kiyoshi Takagawa, Masahiko Kanamori, Hemragul Sabit, Toshiyuki Obata, Tomoatsu Kimura and Masakiyo Sasahara  J. Comp. Neurol. 482(1), 33-49 (2004)  IF:3.672

15)     Inhibition of Akt kinase activity by a peptide spanning the beta A strand of the protooncogene TCL1   Makoto Hiromura, Futoshi Okada, Toshiyuki Obata, Daniel Auguin, Takeshi Shibata, Christian Roumenstand and Masayuki Noguchi  J Biol Chem. 279(51), 53407-53418 (2004)               IF:6.482

16)     The phosphatidylinositol-3 Kinase Pathway Regulates Bladder Cancer Cell Invasion   Xiuli Wu, Toshiyuki Obata, Qiratulanne Khan, Ralph A. Highshaw, Ralph de Vere White and Colleen Sweeney  The British Journal of Urology 93(1), 143-150 (2004)     IF:1.642

17)     Increased insulin sensitivity and hypoinsulinemia in APS knockout mice   Asako Minami, Masanori Iseki, Kazuhiro Kishi, Miao Wang, Makoto Ogura, Noboru Furukawa, Sanae Hayashi, Mizuki Yamada, Toshiyuki Obata, Yukari Takeshita, Yutaka Nakaya, Yoshimi Bando, Keisuke Izumi, Shonna A. Moodie, Fumiko Kajiura, Mitsuru Matsumoto, Kiyoshi Takatsu, Satoshi Takaki and Yousuke Ebina  Diabetes 52, 2657-2665 (Nov 2003)     IF:8.298

18)     Injection of the insulin receptor alpfa subunit increases blood glucose levels in mice   Yoshiko Kanezaki, Rie Matsushima, Toshiyuki Obata, Yutaka Nakaya, Toshio Matsumoto and Yousuke Ebina  Biochem. Biophys. Res. Commun. 309(30) 572-577 (Sep 2003)            IF:2.836

19)     Use of RNA-interference-mediated gene silencing and adenoviral overexpression to Elucidate the roles of AKT/PKB-isoforms in insulin actions   Toshiyuki Obata, Takashi Katome, Rie Matsushima, Norihisa Masuyama, Lewis C. Cantley, Yukiko Gotoh, Kazuhiro Kishi, Hiroshi Shiota and Yousuke Ebina  J. Biol. Chem. 278, 28312-28323 (25 Jul 2003)               IF:6.482

20)     Shikonin Stimulates Glucose Uptake in 3T3-L1 Adipocytes via an Insulin- Independent Tyrosine Kinase Pathway   Reiko Kamei, Yoshinori Kitagawa, Michinori Kadokura, Fumiyuki Hattori, Osamu Hazeki, Yousuke Ebina, Tatsuro Nishihara and Shinzo Oikawa  Biochem. Biophys. Res. Commun. 292, 642-651 (2002)     IF:2.836

21)     Membrane localization of 3-phosphoinositide-dependent protein kinase-1 stimulates activities of Akt and Atypical PKC, but does not stimulate glucose transport and glycogen synthesis in 3T3-L1 adipocytes   Katusya Egawa, Hiroshi Maegawa, Kun Shi, Takaaki Nakamura, Toshiyuki Obata, Takeshi Yoshizaki, Katsutaro Morino, Shinya Shimizu, Yoshihiko, Nishio, Eiji Suzuki, Atsunori Kashiwagi  J. Biol. Chem. 277, 38863-38869 (2002)          IF:6.482

22)     Akt enhances Mdm2-mediated ubiquitination and degradation of p53   Yoko Ogawara, Shohei Kishishita, Toshiyuki Obata, Yuko Isazawa, Toshiaki Suzuki, Keiji Tanaka, Norihisa Masuyama and Yukiko Gotoh  J. Biol. Chem. 277, 21843-21850 (2002)    IF:6.482

23)     Akt/PKB promotes organ growth in transgenic mice   Tetuo Shioi, Julie R. McMullen, Peter M. Kang, Pamela S. Douglas, Toshiyuki Obata, Thomas F. Frank, Lewis C. Cantley and Seigo Izumo  Mol. Cell. Biol. 22, 2799-2809 (2002)              IF:8.142

24)     Differential regulation of Akt kinase isoforms by the members of the TCL1 oncogene family   Jaromo Laine, Gerald Kunstle, Toshiyuki Obata and Masayuki Noguchi.  J. Biol. Chem. 277, 3743-3751 (2002)           IF:6.482

25)     Effects of losartan in combination with or without exercise on insulin resistance in Otsuka Long-Evans Tokushima Fatty rats   Keisuke Ishizawa, Masanori Yoshizumi, Koichiro Tsuchiya, Eiko Takishita, Yutaka Nakaya, Kazuhiro Kishi, Yousuke Ebina, Hitoshi Houchi, Kazuo Minakuchi and Toshiaki Tamaki.  Eur. J. Pharmacol. 430, 359-367 (2001)            IF:2.352

26)     Antisense GLUT-1 protects mesangial cells from glucose induction of GLUT-1 and fibronectin expression   Charles W. Heilig, Jeffrey I. Kreisberg, Svend Freytag, Takashi Murakami, Yousuke Ebina, Lirong Guo, Kathleen Heilig, Robert Loberg, Xuan qu, Ying Jin, Douglas Henry, and Frank C. Brosius III.  Am J Physiol Renal Physiol 280, F657-666 (2001)               IF:4.344

27)     Identification of a cis ? Acting Element and a Noveltrans ? Acting Factor of the Human Insulin Receptor Gene in HepG2 and Rat Liver Cells   Kazuaki Yoshizato, Tetsuya Shirotani, Noboru Furukawa, Tetsuya Taguchi, Hiroyuki Motoshima, Tetsushi Toyonaga, Yoshiaki Hirashima, Junji Kawashima, Yousuke Ebina, Motoaki Shichiri and Eiichi Araki.  Biochem. Biophys. Res. Commun. 280, 428-434 (2001)   IF:2.836

28)     A motif-based profile scanning approach for genome-wide prediction of signaling pathways   Michael B. Yaffe, German G. Leparc, Jack Lai, Toshiyuki Obata, Stefano Volinia and Lewis C. Cantley  Nature Biotechnol. 19, 348-353 (2001)               IF:17.721

29)     AMP-activated protein kinase is activated by the stimulations of Gq-coupled receptors   Kazuhiro Kishi, Tomoyuki Yuasa, Asako Minami, Mizuki Yamada, Akifumi Hagi, Hideki Hayashi, Bruce E. Kemp, Lee A. Witters and Yousuke Ebina.  Biochem. Biophys. Res. Commun. 276, 16-22 (2000)     IF:2.836

30)     Activation of G-protein coupled fMLP or PAF receptor directly triggers glucose transporter type 1 (GLUT1) translocation in Chinese hamster ovary (CHO) cells stably expressing fMLP or PAF receptor   Akifumi Hagi, Hideki Hayashi, Kazuhiro Kishi, Lihong Wang and Yousuke Ebina  The Journal of Medical Investigation 47(1-2) (2000)    IF:0

31)     Overexpression of wild-type Akt1 promoted insulin-stimulated p70S6 kinase (p70S6K) activity and affected GSK3b regulation, but did not promote insulin-stimulated GLUT4 translocation or glucose transport in L6 myotubes   Satoshi Noda, Kazuhiro Kishi, Tomoyuki Yuasa, Hideki Hayashi, Tetuo Ohnishi, Ikuko Miyata, Hiromu Nishitani and Yousuke Ebina  The Journal of Medical Investigation 47(1-2) (2000)      IF:0

32)     Gi-mediated translocation of GLUT4 is independent of p85/p110a?and p110g phosphoinositide 3-kinases but might involve the activation of Akt kinase   Lihong Wang, Hideki Hayashi, Kazuhiro Kishi, Luping Huang, Akifumi Hagi, Keisuke Tamaoka, Phillip T. Hawkins and Yousuke Ebina  Biochem. J. 345, 543-555 (2000)     IF:4.101

33)     The protooncogene TCL1 is an Akt kinase coactivator   Jarmo Laine, Gerald Kunstle, Toshiyuki Obata, Ma Sha and Masayuki Noguchi.  Mol. Cell. 6, 395-407 (2000)           IF:16.835

34)     MAP kinase pathways activated by stress: the p38 MAPK pathway   Toshiyuki Obata, Glenn E. Brown and Michael B. Yaffe  Crit. Care Med. 28, N67-77 (2000)        IF:4.195

35)     Peptide and Protein Library Screening Defines Optimal Substrate Motifs for AKT/PKB   Toshiyuki Obata, Michael B. Yaffe, German G. Leparc, Elizabeth T. Piro, Hiroshi Maegawa, Atsunori Kashiwagi, Ryuichi Kikkawa and Lewis C. Cantley  J. Biol. Chem. 275, 36108-36115 (2000) IF:6.482

36)     Association of Stomatin (Band 7.2b) with Glut 1 Glucose Transporter   Jin-Zhong Zhang, Hideki Hayashi, Yousuke Ebina, Rainer Prohaska and Faramarz Ismail-Beigi.  Archives of Biochemistry and Biophysics 372(1), 173-178 (1999)               IF:2.338

37)     Fluoromicroscopic detection of myc-tagged GLUT4 on the cell surface. Co-localization of the translocated GLUT4 with rearranged actin by insulin teatment in CHO cells and L6 myotubes   Yoshihiko Asahi, Hideki Hayashi, Lihong Wang and Yousuke Ebina.  The Journal of Medical Investigation 46(3-4) (1999)         IF:0

38)     GLUT-4myc ectopic expression in L6 myoblasts generates a GLUT-4-specific pool conferring insulin sensitivity   Atsunori Ueyama, Karen L. Yaworsky, Qinghua Wang, Yousuke Ebina and Amira Klip.  Am. J. Physiol. 277, E572-E578 (1999)               IF:3.828

39)     Mutation of Tyrosine 960 within the Insulin Receptor Juxtamembrane Domain Impairs Glucose Transport but Dose Not Inhibit Ligand-mediated Phosphorylation of Insulin Receptor Substrate-2 in 3T3-L1 Adipocytes   Oleg V. Chaika, Nina Chaika, Deanna J. Volle, Hideki Hayashi, Yousuke Ebina, Ling-Mei Wang, Jacalyn H. Piece and Robert E. Lewis.  J. Biol. Chem. 274, 12075-12080 (1999)        IF:6.482

40)     Transient Effect of Platelet-derived Growth Factor (PDGF) on GLUT4 Translocation in 3T3-L1 Adipocytes   Lihong Wang, Hideki Hayashi and Yousuke Ebina.  J. Biol. Chem. 274, 19246-19253 (1999)   IF:6.482

41)     Effect of growth hormone on the translocation of GLUT4 and its relation to insulin-like and anti-insulin action   Ichiro Yokota, Hideki Hayashi, Junko Matsuda, Takahiko Saijo, Etsuo Naito, Michinori Ito, Yousuke Ebina and Yasuhiro Kuroda.  Biochimica et Biophysica Acta 1404, 451-456 (1998)      IF:3.594

42)     Impaired glucose tolerance in mice with a targeted impairment of insulin action in muscle and adipose tissue   Davide Lauro, Yoshiaki Kido, Arthur L. Castle, Mary-Jane Zarnowski, Hideki Hayashi, Yousuke Ebina and Domenico Accili.  Nature Genetics. 20, 294-298 (1998)             IF:26.494

43)     Rapid stimulation of glucose transport by mitochondrial uncoupling depends in part on cytosolic Ca2+ and cPKC   Zayna Khayat, Theodoros Tsakiridis, Atsunori Ueyama, Romel Somwar, Yousuke Ebina and Amira Klip.  Am. J. Physiol. 275(6 Pt1), C1487-1497 (1998)     IF:3.828

44)     Reconstitution of Insulin Signaling Pathways in Rat 3Y1 Cells Lacking Insulin Receptor and Insulin Receptor Substrate-1   Takanobu Imanaka, Hideki Hayashi, Kazuhiro Kishi, Lihong Wang, Kazuo Ishii, Osamu Hazeki, Toshiaki Katada and Yousuke Ebina.  J. Biol. Chem. 273, 25347-25355 (1998)            IF:6.482

45)     GLUT4 translocation by insulin in intact muscle cells: detection by a fast and quantitative assay   Qinghua Wang, Zayna Khayat, Kazuhiro Kishi, Yousuke Ebina and Amira Klip.  FEBS Letters 427, 193-197 (1998)        IF:3.609

46)     Insulin enhances macrophage scavenger receptor-mediated endocytic uptake of advanced glycation end products   Hiroyuki Sano, Takayuki Higashi, Kenshi Matsumoto, Jukka Melkko, Yoshiteru Jinnouchi, Kazuyoshi Ikeda, Yousuke Ebina, Hideichi Makino, Bard Smedsrod and Seikoh Horiuchi.  J. Biol. Chem. 273, 8630-8637 (1998)   IF:6.482

47)     Bradykinin directly triggers GLUT4 translocation via an insulin-independent pathway   Kazuhiro Kishi, Naoko Muromoto, Yutaka Nakaya, Ikuko Miyata, Akifumi Hagi, Hideki Hayashi and Yousuke Ebina.  Diabetes 47, 550-558 (1998)               IF:8.298

48)     Transcriptional activation of the Glut1 gene in response to oxidative stress in L6 myotubes   Nitzan Kozlovsky, Assaf Rudich, Ruth Potashnik, Yousuke Ebina, Takashi Murakami and Nava Bashan.  J. Biol. Chem. 272, 33367-33372 (1997)               IF:6.482

49)     Hyperinsulinemia but no diabetes in transgenic mice homozygously expressing the tyrosine kinase-deficient human insulin receptor   Lihong Wang, Naoko Muromoto, Hideki Hayashi, Yasumasa Mitani, Hisanori Uehara, Keisuke Izumi and Yousuke Ebina.  Biochem. Biophys. Res. Commun. 240, 446-451 (1997)     IF: 2.836

50)     Acute stimulation of glucose metabolism in mice by leptin treatment   Seika Kamohara, Remy Burcelin, Jeffrey L. Halaas, Jeffrey M. Friedman and Maureen J. Charron.  Nature 389, 374-377 (1997)               IF:30.979