T Yoshimura

Nagoya University, Nagoya, Aichi, Japan

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Publications (90)519.94 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Semaphorin3A (Sema3A) is a repulsive guidance molecule for axons, which acts by inducing growth cone collapse through phosphorylation of CRMP2 (collapsin response mediator protein 2). Here, we show a role for CRMP2 oxidation and thioredoxin (TRX) in the regulation of CRMP2 phosphorylation and growth cone collapse. Sema3A stimulation generated hydrogen peroxide (H2O2) through MICAL (molecule interacting with CasL) and oxidized CRMP2, enabling it to form a disulfide-linked homodimer through cysteine-504. Oxidized CRMP2 then formed a transient disulfide-linked complex with TRX, which stimulated CRMP2 phosphorylation by glycogen synthase kinase-3, leading to growth cone collapse. We also reconstituted oxidation-dependent phosphorylation of CRMP2 in vitro, using a limited set of purified proteins. Our results not only clarify the importance of H2O2 and CRMP2 oxidation in Sema3A-induced growth cone collapse but also indicate an unappreciated role for TRX in linking CRMP2 oxidation to phosphorylation.
    Science Signaling 01/2011; 4(170):ra26. · 7.65 Impact Factor
  • T. Yoshimura, N. Arimura, K. Kaibuchi
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    ABSTRACT: A mature neuron is typically polarized with a single long axon and several dendrites. After the birth and differentiation of a neuron, a neuron breaks its previous symmetry and establishes an axon and dendrites. Neuronal polarization occurs when one of the multiple immature neurites emerging from the cell body elongates rapidly. This neurite becomes the axon, whereas the remaining immature neurites become dendrites. What are the molecular mechanisms specifying the axon in the initial events? Here we provide an overview of recent progress into the study of axon formation.
    12/2008: pages 27-37;
  • Nariko Arimura, Takeshi Yoshimura, Kozo Kaibuchi
    Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme 03/2008; 53(4 Suppl):386-92.
  • Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme 07/2007; 52(7):753-9.
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    ABSTRACT: Rac1 and Cdc42, members of the Rho family GTPases, control diverse cellular processes such as cell migration and morphogenesis through their effectors. Among the effectors, IQGAP1 plays pivotal roles in the establishment of cytoskeletal architecture and intercellular adhesions in various cells. However, its roles remain to be clarified, especially in neuronal cells. We have identified IQGAP3 as a novel member of the IQGAP family, which is highly expressed in brain. We found that IQGAP3, an effector of Rac1 and Cdc42, associates directly with actin filaments and accumulates asymmetrically at the distal region of axons in hippocampal neurons. The depletion of IQGAP3 impairs neurite or axon outgrowth in neuronal cells with the disorganized cytoskeleton, but depletion of IQGAP1 does not. Furthermore, IQGAP3 is indispensable for Rac1/Cdc42-promoted neurite outgrowth in PC12 cells. Taken together, these results indicate that IQGAP3 can link the activation of Rac1 and Cdc42 with the cytoskeletal architectures during neuronal morphogenesis.
    Journal of Cell Science 03/2007; 120(Pt 4):567-77. · 5.88 Impact Factor
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    ABSTRACT: Glycogen synthase kinase-3beta (GSK-3beta) is thought to mediate morphological responses to a variety of extracellular signals. Surprisingly, we found no gross morphological deficits in nervous system development in GSK-3beta null mice. We therefore designed an shRNA that targeted both GSK-3 isoforms. Strong knockdown of both GSK-3alpha and beta markedly reduced axon growth in dissociated cultures and slice preparations. We then assessed the role of different GSK-3 substrates in regulating axon morphology. Elimination of activity toward primed substrates only using the GSK-3 R96A mutant was associated with a defect in axon polarity (axon branching) compared to an overall reduction in axon growth induced by a kinase-dead mutant. Consistent with this finding, moderate reduction of GSK-3 activity by pharmacological inhibitors induced axon branching and was associated primarily with effects on primed substrates. Our results suggest that GSK-3 is a downstream convergent point for many axon growth regulatory pathways and that differential regulation of primed versus all GSK-3 substrates is associated with a specific morphological outcome.
    Neuron 01/2007; 52(6):981-96. · 15.77 Impact Factor
  • Takeshi Yoshimura, Nariko Arimura, Kozo Kaibuchi
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    ABSTRACT: A cardinal feature of neurons is the morphological polarity of neurons with serious functional implications. Typically, a neuron has a single axon and several dendrites. Neuronal polarity is essential for the unidirectional signal flow from somata or dendrites to axons in neurons. The initial event in establishing a polarized neuron is the specification of a single axon. Although researchers are accumulating a catalog of structural, molecular, and functional differences between axons and dendrites, we are only now beginning to understand the molecular mechanisms involved in the establishment of neuronal polarity. We have described recent advances in the understanding of cellular events in the early development of an axon and dendrites. Several groups, including ours, reported that the phosphatidylinositol 3-kinase (PI3-kinase)/Akt (also called protein kinase B)/glycogen synthase kinase-3beta (GSK-3beta)/collapsin response mediator protein-2 (CRMP-2) pathway is important for axon specification and elongation. Recent studies have revealed the roles that Rho family small GTPases, the Par complex, and cytoskeleton-related proteins play in the initial events of neuronal polarization downstream of PI3-kinase. We discuss the roles of polarity-regulating molecules and the potential mechanisms underlying the specification of an axon and dendrites. Polarity-regulating molecules participate in various neuronal disorders. In this review, the signal transduction of GSK-3beta and CRMP-2 is introduced as a new target for the treatment of Alzheimer's disease (AD) and nerve injury. These findings may help clarify causes of and treatments aimed at reversing AD and nerve injury.
    Annals of the New York Academy of Sciences 12/2006; 1086:116-25. · 4.38 Impact Factor
  • Takeshi Yoshimura, Nariko Arimura, Kozo Kaibuchi
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    ABSTRACT: A mature neuron is typically polarized both structurally and functionally, with a single long axon and several dendrites. Neuronal polarity is essential for unidirectional signal flow from somata or dendrites to axons. The initial event in establishing a polarized neuron is the specification of a single axon. Early in neuronal development, one immature neurite becomes differentiated from other neurites to form an axon. Although studies in the past two decades have yielded a catalog of structural, molecular, and functional differences between axons and dendrites, we are only now beginning to understand the molecular mechanisms involved in the establishment of neuronal polarity. In the last few years, neuronal polarity-regulating molecules have been revealed. There are two major signaling cascades in neuronal polarization. Several groups, including ours, reported that the phosphatidylinositol 3-kinase (PI3-kinase)/Akt/glycogen synthase kinase-3beta (GSK-3beta)/collapsin response mediator protein-2 pathway is important for axon specification and elongation. Recent studies have revealed that the positive feedback loop composed of Rho family small GTPases and the Par3/Par6/atypical protein kinase C complex plays a role in the initial events of neuronal polarization downstream of PI3-kinase. Here, we discuss the roles of signaling molecules for axon specification.
    Journal of Neuroscience 11/2006; 26(42):10626-30. · 6.91 Impact Factor
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    ABSTRACT: Rho belongs to the Rho family guanosine triphosphatases (GTPases) including Rho, Rac, Cdc42, TC10, and so on. Rho is categorized into RhoA, B, and C. The Rho family GTPases exhibit guanine nucleotide-binding activity and function as molecular switches by cycling between an inactive guanosine diphosphate (GDP)-bound form and an active GTP-bound form. Rho participates in the regulation of actin cytoskeletons, cell adhesions, cytokinesis, smooth muscle contraction, cell morphology, cell motility, neurite retraction, and polarity formation through their specific effectors. The characterization of these effectors has begun to clarify how Rho regulates some phenotypes. This article focuses on the roles of RhoA/C and their effectors.
    03/2006: pages 113-136;
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    ABSTRACT: The establishment of a polarized morphology is an essential event in the differentiation of neurons into a single axon and dendrites. We previously showed that glycogen synthase kinase-3beta (GSK-3beta) is critical for specifying axon/dendrite fate by the regulation of the phosphorylation of collapsin response mediator protein-2 (CRMP-2). Here, we found that the overexpression of the small GTPase Ras induced the formation of multiple axons in cultured hippocampal neurons, whereas the ectopic expression of the dominant negative form of Ras inhibited the formation of axons. Inhibition of phosphatidylinositol-3-kinase (PI3-kinase) or extracellular signal-related kinase (ERK) kinase (MEK) suppressed the Ras-induced formation of multiple axons. The expression of the constitutively active form of PI3-kinase or Akt (also called protein kinase B) induced the formation of multiple axons. The overexpression of Ras prevented the phosphorylation of CRMP-2 by GSK-3beta. Taken together, these results suggest that Ras plays critical roles in establishing neuronal polarity upstream of the PI3-kinase/Akt/GSK-3beta/CRMP-2 pathway and mitogen-activated protein kinase cascade.
    Biochemical and Biophysical Research Communications 03/2006; 340(1):62-8. · 2.41 Impact Factor
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    ABSTRACT: A neuron has two types of highly polarized cell processes, the single axon and multiple dendrites. One of the fundamental questions of neurobiology is how neurons acquire such specific and polarized morphologies. During neuronal development, various actin-binding proteins regulate dynamics of actin cytoskeleton in the growth cones of developing axons. The regulation of actin cytoskeleton in the growth cones is thought to be involved in axon outgrowth and axon-dendrite specification. However, it is largely unknown which actin-binding proteins are involved in axon-dendrite specification and how they are transported into the developing axons. We have previously reported that collapsin response mediator protein 2 (CRMP-2) plays a critical role in axon outgrowth and axon-dendrite specification (N. Inagaki, K. Chihara, N. Arimura, C. Menager, Y. Kawano, N. Matsuo, T. Nishimura, M. Amano, and K. Kaibuchi, Nat. Neurosci. 4:781-782, 2001). Here, we found that CRMP-2 interacted with the specifically Rac1-associated protein 1 (Sra-1)/WASP family verprolin-homologous protein 1 (WAVE1) complex, which is a regulator of actin cytoskeleton. The knockdown of Sra-1 and WAVE1 by RNA interference canceled CRMP-2-induced axon outgrowth and multiple-axon formation in cultured hippocampal neurons. We also found that CRMP-2 interacted with the light chain of kinesin-1 and linked kinesin-1 to the Sra-1/WAVE1 complex. The knockdown of CRMP-2 and kinesin-1 delocalized Sra-1 and WAVE1 from the growth cones of axons. These results suggest that CRMP-2 transports the Sra-1/WAVE1 complex to axons in a kinesin-1-dependent manner and thereby regulates axon outgrowth and formation.
    Molecular and Cellular Biology 12/2005; 25(22):9920-35. · 5.37 Impact Factor
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    ABSTRACT: Collapsin response mediator protein 2 (CRMP-2) enhances the advance of growth cones by regulating microtubule assembly and Numb-mediated endocytosis. We previously showed that Rho kinase phosphorylates CRMP-2 during growth cone collapse; however, the roles of phosphorylated CRMP-2 in growth cone collapse remain to be clarified. Here, we report that CRMP-2 phosphorylation by Rho kinase cancels the binding activity to the tubulin dimer, microtubules, or Numb. CRMP-2 binds to actin, but its binding is not affected by phosphorylation. Electron microscopy revealed that CRMP-2 localizes on microtubules, clathrin-coated pits, and actin filaments in dorsal root ganglion neuron growth cones, while phosphorylated CRMP-2 localizes only on actin filaments. The phosphomimic mutant of CRMP-2 has a weakened ability to enhance neurite elongation. Furthermore, ephrin-A5 induces phosphorylation of CRMP-2 via Rho kinase during growth cone collapse. Taken together, these results suggest that Rho kinase phosphorylates CRMP-2, and inactivates the ability of CRMP-2 to promote microtubule assembly and Numb-mediated endocytosis, during growth cone collapse.
    Molecular and Cellular Biology 12/2005; 25(22):9973-84. · 5.37 Impact Factor
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    ABSTRACT: Neurons are one of the most highly polarized cells known and are comprised of two structurally and functionally distinct parts, an axon and dendrites. The specification of the axon is thought to depend on its length relative to the other minor processes, which are called immature neurites. Elongation of one of immature neurites is necessary for axon specification. We previously showed that collapsin response mediator protein-2 (CRMP-2) is critical for specifying axon/dendrite fate, possibly by promoting neurite elongation via microtubule assembly. Here, we showed that glycogen synthase kinase-3beta (GSK-3beta) phosphorylated CRMP-2 at Thr-514 and inactivated it. The expression of the nonphosphorylated form of CRMP-2 or inhibition of GSK-3beta induced the formation of multiple axons in hippocampal neurons. The expression of constitutively active GSK-3beta impaired neuronal polarization, whereas the nonphosphorylated form of CRMP-2 counteracted the inhibitory effects of GSK-3beta, indicating that GSK-3beta regulates neuronal polarity through the phosphorylation of CRMP-2. We here reviewed the molecular mechanisms of the axon formation.
    Nihon shinkei seishin yakurigaku zasshi = Japanese journal of psychopharmacology 09/2005; 25(4):169-74.
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    ABSTRACT: Neurons are highly polarized and comprised of two structurally and functionally distinct parts, an axon and dendrites. We previously showed that collapsin response mediator protein-2 (CRMP-2) is critical for specifying axon/dendrite fate, possibly by promoting neurite elongation via microtubule assembly. Here, we showed that glycogen synthase kinase-3beta (GSK-3beta) phosphorylated CRMP-2 at Thr-514 and inactivated it. The expression of the nonphosphorylated form of CRMP-2 or inhibition of GSK-3beta induced the formation of multiple axon-like neurites in hippocampal neurons. The expression of constitutively active GSK-3beta impaired neuronal polarization, whereas the nonphosphorylated form of CRMP-2 counteracted the inhibitory effects of GSK-3beta, indicating that GSK-3beta regulates neuronal polarity through the phosphorylation of CRMP-2. Treatment of hippocampal neurons with neurotrophin-3 (NT-3) induced inactivation of GSK-3beta and dephosphorylation of CRMP-2. Knockdown of CRMP-2 inhibited NT-3-induced axon outgrowth. These results suggest that NT-3 decreases phosphorylated CRMP-2 and increases nonphosphorylated active CRMP-2, thereby promoting axon outgrowth.
    Cell 02/2005; 120(1):137-49. · 31.96 Impact Factor
  • Yoji Kawano, Takeshi Yoshimura, Kozo Kaibuchi
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    ABSTRACT: An increment in a cytoplasmic Ca2+ concentration is the key event in smooth muscle contraction. However, smooth muscle contraction is modified upon the stimulation by agonists as well as in some pathophysiological situations through a Ca(2+)-independent mechanism. The molecular mechanism underlying this modulation has not been elucidated. Small GTPase Rho regulates cytoskeleton, cell adhesion, cell motility, and smooth muscle contraction through its specific effector proteins. Recent studies have shown the important role of Rho and its effector, Rho-associated kinase (Rho-kinase)/ROK/ROCK in Ca(2+)-independent regulation of smooth muscle contraction. The Rho/Rho-kinase pathway is involved in cardiovascular diseases such as hypertension and vasospasm, and it is a potent target of new therapies for not only cardiovascular diseases, but also for the protection of multiple organs.
    Folia Pharmacologica Japonica 10/2002; 120(3):149-58.
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    Yoji Kawano, Takeshi Yoshimura, Kozo Kaibuchi
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    ABSTRACT: Abnormal contraction of vascular smooth muscle contributes to a variety of diseases such as hypertension and vasospasm in coronary and cerebral arteries. An increment in a cytoplasmic Ca2+ concentration is the key event in smooth muscle contraction. However, smooth muscle contraction is modified upon the stimulation by agonists as well as in some pathophysiological situations in Ca(2+)-independent mechanism. The molecular mechanism underlying this modulation was not elucidated. Recent studies have shown the important role of small GTPase Rho and its effector, Rho-associated kinase (Rho-kinase)/ROK/ROCK in Ca(2+)-independent regulation of smooth muscle contraction. The Rho/Rho-kinase pathway modulates the phosphorylation level of myosin light chain (MLC) of myosin II, mainly through the inhibition of myosin phosphatase, and contributes to the agonist-induced Ca(2+)-sensitization in smooth muscle contraction. The Rho/Rho-kinase pathway is involved in the pathogenesis of hypertension, vasospasm and arteriosclerosis, and is a potent target of new therapies for these diseases.
    Nagoya journal of medical science 06/2002; 65(1-2):1-8.
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    ABSTRACT: Although integrins are crucial for migration of leukocytes through endothelium, integrin-independent mechanisms appear to take over and mediate the migration of leukocytes through extracellular matrix (ECM) in a three-dimensional tissue microenvironment. Discoidin domain receptor (DDR) 1 is a receptor tyrosine kinase activated by collagen, the most abundant ECM protein. In the present study, we detected that peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophils were induced to express DDR1 after incubation in RPMI 1640. The expression level of DDR1 in PBMC was increased further by stimulation with tumor necrosis factor-alpha, interleukin-1beta, granulocyte-macrophage colony-stimulating factor, lipopolysaccharide, or phytohemagglutinin, but not with interferon-gamma. In vivo, DDR1 mRNA was detectable in mononuclear leukocytes infiltrating human renal tumor tissue. Among three DDR1 isoforms, DDR1alpha was the major transcript in leukocytes. Functionally, overexpression of either DDR1alpha or DDR1beta in THP-1 cells resulted in increased adherence to collagen-coated plates in a beta1-integrin independent manner. However, only DDR1alpha-, but not DDR1beta-, overexpressing cells exhibited marked pseudopod extension and migrated successfully through three-dimensional collagen lattices. Consequently, we propose that the interaction of DDR1alpha with collagen of the ECM results in a requisite intracellular signaling that enables leukocytes to migrate in a tissue microenvironment and participate in host defense.
    The FASEB Journal 01/2002; 15(14):2724-6. · 5.70 Impact Factor
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    ABSTRACT: Recently, it was shown that Rho-kinase plays an important role in blood pressure regulation. However, it is not known whether Rho-kinase is involved in atherogenesis. Monocyte chemoattractant protein-1 (MCP-1) is an important chemokine that regulates monocyte recruitment and atherogenesis. Therefore, we examined the role of Rho and Rho-kinase in the angiotensin (Ang) II-induced expression of MCP-1. Ang II dose- and time-dependently enhanced the expression of MCP-1 mRNA and the protein production in vascular smooth muscle cells. CV11974, an Ang II type 1 receptor (AT(1)-R) specific antagonist inhibited the enhancement of MCP-1 expression by Ang II, suggesting that the effect of Ang II is mediated by the AT(1)-R. Botulinum C3 exotoxin, a specific inhibitor of Rho, suppressed Ang II-induced MCP-1 production. To examine the role of Rho-kinase in Ang II-induced MCP-1 expression, we used adenovirus-mediated overexpression of the dominant negative mutant of Rho-kinase (AdDNRhoK) or Y-27632, a specific inhibitor of Rho-kinase. Both AdDNRhoK and Y-27632 strongly inhibited Ang II-induced MCP-1 expression. Although inhibition of extracellular signal-regulated protein kinase (ERK) by PD 098,059 also inhibited Ang II-induced MCP-1 expression, Y-27632 did not affect Ang II-induced activation of ERK. These results indicate that Rho-kinase plays a critical role in Ang II-induced MCP-1 production independent of ERK. The Rho-Rho-kinase pathway may be a novel target for the inhibition of Ang II signaling and the treatment of atherosclerosis.
    Hypertension 08/2001; 38(1):100-4. · 6.87 Impact Factor
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    ABSTRACT: Polymorphonuclear leukocytes (PMN) are the most abundant leukocytes, comprising about two-thirds of peripheral blood leukocytes, and play major roles in innate immunity. In addition, PMN play critical roles in the development of adaptive immunity. Recently, defensins and other peptides pre-stored in PMN granules were shown to attract monocytes, dendritic cells, and T cells, leading to the hypothesis that the release of PMN granular peptides may link innate and adaptive immunity. During the past several years, we have focused on an alternative hypothesis that activated PMN further differentiate and acquire new phenotypes and functions that enable them to link the two responses. To test our hypothesis, we have taken local and global approaches and have shown several key findings that support the hypothesis. The findings include the requirement for priming PMN by cytokines to induce the delayed expression of MCP-1/CCL2, a signal for mononuclear cells, and the expression of new cell-surface markers by such cytokine-activated PMN. In the present manuscript, we focus on the phenotypic and functional changes that occur during PMN activation with selected cytokines. The results of our study indicate that inflammatory PMN are heterogeneous and play roles in not only innate but also adaptive immunity in response to stimuli released in injured tissues.
    Journal of Leukocyte Biology 06/2001; 69(5):698-704. · 4.57 Impact Factor
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    ABSTRACT: In this study, we attempted to analyze the peptide motifs recognized by 24822.111 and F9, monoclonal antibodies (mAbs) that inhibit the chemotactic activity of monocyte chemoattractant protein-1 (MCP-1), a member of the CC subfamily of chemokines. We isolated phage clones from a phage display library and identified six peptide motifs. One of these clones, C27, was strongly and specifically recognized by 24822.111 mAb, while another, G25, was similarly recognized by F9 mAb. Both the C27 motif and the G25 motif contain two cysteines in their sequences and have little homology to the primary amino acid sequence of MCP-1. These clones, however, bound to THP-1 cells, and the binding was competitively inhibited by MCP-1. The clones strongly inhibited the MCP-1-induced chemotaxis of human monocytes. The synthetic and intramolecularly disulfide-linked peptides of C27 and G25 (sC27 and sG25) also inhibited the chemotaxis induced by MCP-1, while their derivatives with serine in place of cysteine did not, suggesting the importance of the loop structure for the inhibition. These results suggest that sC27 and sG25 may mimic the MCP-1-binding domain to the MCP-1 receptor.
    Journal of Biochemistry 05/2001; 129(4):577-83. · 3.07 Impact Factor

Publication Stats

7k Citations
519.94 Total Impact Points

Institutions

  • 2002–2007
    • Nagoya University
      • Graduate School of Medicine
      Nagoya, Aichi, Japan
  • 2005
    • Dokkyo Medical University
      • Department of Molecular and Cell Biology
      Tochigi, Tochigi-ken, Japan
  • 1990–2002
    • Leidos Biomedical Research
      Maryland, United States
    • Yale University
      • Department of Internal Medicine
      New Haven, CT, United States
  • 1998–2000
    • Kyushu University
      • • Department of Cardiovascular Medicine
      • • Faculty of Medical Sciences
      Fukuoka-shi, Fukuoka-ken, Japan
  • 1996–1999
    • NCI-Frederick
      Maryland, United States
  • 1994–1999
    • National Institutes of Health
      • Section of Inflammation Immunobiology
      Maryland, United States
    • Kumamoto University
      • Department of Neurosurgery
      Kumamoto, Kumamoto Prefecture, Japan
  • 1986–1997
    • National Cancer Institute (USA)
      • Laboratory of Tumor Immunology and Biology
      Maryland, United States
  • 1989
    • National Institute of Allergy and Infectious Diseases
      Maryland, United States