Yuichi Takakuwa

Tokyo Women's Medical University, Edo, Tōkyō, Japan

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Publications (84)301.18 Total impact

  • Yuichi Takakuwa, Nobuto Arashiki, Masaki Saito
    [Rinshō ketsueki] The Japanese journal of clinical hematology 06/2014; 55(6):643-50.
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    ABSTRACT: Membrane skeletal protein 4.1R(80) plays a key role in regulation of erythrocyte plasticity. Protein 4.1R(80) interactions with transmembrane proteins, such as glycophorin C (GPC), are regulated by Ca(2+)-saturated calmodulin (Ca(2+)/CaM) through simultaneous binding to a short peptide (pep11; A(264)KKLWKVCVEHHTFFRL) and a serine residue (Ser(185)), both located in the N-terminal 30kDa FERM domain of 4.1R(80) (H·R30). We have previously demonstrated that CaM binding to H·R30 is Ca(2+)-independent and that CaM binding to H·R30 is responsible for the maintenance of H·R30 β-sheet structure. However, the mechanisms responsible for the regulation of CaM binding to H·R30 are still unknown. To investigate this, we took advantage of similarities and differences in the structure of Coracle, the Drosophila sp. homologue of human 4.1R(80), i.e conservation of the pep11 sequence but substitution of the Ser(185) residue with an alanine residue. We show that the H·R30 homologue domain of Coracle, Cor30, also binds to CaM in a Ca(2+)-independent manner and that the Ca(2+)/CaM complex does not affect Cor30 binding to the transmembrane protein GPC. We also document that both H·R30 and Cor30 bind to phosphatidylinositol- 4,5 bisphosphate (PIP2) and other phospholipid species and that that PIP2 inhibits Ca(2+)-free CaM but not Ca(2+)-saturated CaM binding to Cor30. We conclude that PIP2 may play an important role as a modulator of apo-CaM binding to 4.1R(80) throughout evolution.
    Biochemical and Biophysical Research Communications 03/2014; · 2.41 Impact Factor
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    Wataru Nunomura, Hideki Wakui, Yuichi Takakuwa
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    ABSTRACT: An intriguing observation is that human erythrocytes can maintain their structural integrity over their 120-day life span despite the fact that they can no longer synthesize new proteins as they undergo enucleation upon maturation. Calmodulin (CaM), a canonical Ca 2+ binding protein, plays a key role in keeping homeostasis
    Biohelikon Cell Biology. 02/2014;
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    ABSTRACT: Membrane skeletal protein 4.1R80 plays a key role in regulation of erythrocyte plasticity. Protein 4.1R80 interactions with transmembrane proteins, such as glycophorin C (GPC), are regulated by Ca2+-saturated calmodulin (Ca2+/CaM) through simultaneous binding to a short peptide (pep11; A264KKLWKVCVEHHTFFRL) and a serine residue (Ser185), both located in the N-terminal 30kDa FERM domain of 4.1R80 (H·R30). We have previously demonstrated that CaM binding to H·R30 is Ca2+-independent and that CaM binding to H·R30 is responsible for the maintenance of H·R30 β-sheet structure. However, the mechanisms responsible for the regulation of CaM binding to H·R30 are still unknown. To investigate this, we took advantage of similarities and differences in the structure of Coracle, the Drosophila sp. homologue of human 4.1R80, i.e conservation of the pep11 sequence but substitution of the Ser185 residue with an alanine residue. We show that the H·R30 homologue domain of Coracle, Cor30, also binds to CaM in a Ca2+-independent manner and that the Ca2+/CaM complex does not affect Cor30 binding to the transmembrane protein GPC. We also document that both H·R30 and Cor30 bind to phosphatidylinositol- 4,5 bisphosphate (PIP2) and other phospholipid species and that that PIP2 inhibits Ca2+-free CaM but not Ca2+-saturated CaM binding to Cor30. We conclude that PIP2 may play an important role as a modulator of apo-CaM binding to 4.1R80 throughout evolution.
    Biochemical and Biophysical Research Communications 01/2014; · 2.41 Impact Factor
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    ABSTRACT: Calmodulin (CaM) binds to the FERM domain of 80 kDa erythrocyte protein 4.1R (R30) independently of Ca(2+) but, paradoxically, regulates R30 binding to transmembrane proteins in a Ca(2+)-dependent manner. We have previously mapped a Ca(2+)-independent CaM-binding site, pep11 (A(264)KKLWKVCVEHHTFFR), in 4.1R FERM domain and demonstrated that CaM, when saturated by Ca(2+) (Ca(2+)/CaM), interacts simultaneously with pep11 and with Ser(185) in A(181)KKLSMYGVDLHKAKD (pep9), the binding affinity of Ca(2+)/CaM for pep9 increasing dramatically in the presence of pep11. Based on these findings, we hypothesized that pep11 induced key conformational changes in the Ca(2+)/CaM complex. By differential scanning calorimetry analysis, we established that the C-lobe of CaM was more stable when bound to pep11 either in the presence or absence of Ca(2+). Using nuclear magnetic resonance spectroscopy, we identified 8 residues in the N-lobe and 14 residues in the C-lobe of pep11 involved in interaction with CaM in both of presence and absence of Ca(2+). Lastly, Kratky plots, generated by small-angle X-ray scattering analysis, indicated that the pep11/Ca(2+)/CaM complex adopted a relaxed globular shape. We propose that these unique properties may account in part for the previously described Ca(2+)/CaM-dependent regulation of R30 binding to membrane proteins.
    Cell biochemistry and biophysics 10/2013; · 3.34 Impact Factor
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    ABSTRACT: Oxidative damage and clustering of band 3 in the membrane have been implicated in the removal of senescent human erythrocytes from the circulation at the end of their 120-day life span. However, the biochemical and mechanistic events leading to band 3 cluster formation have yet to be fully defined. Here we show that while neither membrane peroxidation nor MetHb formation on their own can induce band 3 clustering in the human erythrocytes, they can do so when acting in combination. We further show that MetHb binding to the cytoplasmic domain of band 3 in peroxidized, but not in untreated erythrocyte membranes, induces cluster formation. Age-fractionated populations of erythrocytes from normal human blood, obtained by a density-gradient procedure, have enabled us to examine a subpopulation, highly enriched in senescent cells. We have found that band 3 clustering is a feature of only this small fraction, amounting to ~ 0.1% of total circulating erythrocytes. These senescent cells are characterized by an increased proportion of MetHb as a result of reduced NADH-dependent reductase activity, and accumulated oxidative membrane damage. These findings have enabled us to establish that the combined effects of membrane peroxidation and MetHb formation are necessary for band 3 clustering, and this is a very late event in erythrocyte life. A plausible mechanism for the combined effects of membrane peroxidation and MetHb is proposed, involving high-affinity cooperative binding of MetHb to the cytoplasmic domain of oxidized band 3, probably due to its carbonylation, rather than other forms of oxidative damage. This modification leads to dissociation of ankyrin from the band 3, enabling the tetrameric MetHb to cross-link the resulting freely diffusible band 3 dimers, with formation of clusters.
    Biochemistry 07/2013; · 3.38 Impact Factor
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    Hattori M, Nunomura W, Ito E, Ohta H, Takakuwa Y
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    ABSTRACT: The classical function of 4.1R in erythrocytes is to contribute to the mechanical properties of the membrane by promoting the interaction between spectrin and actin. It is now well recognized that 4.1R is required for the stable anchorage of numerous cell surface erythrocyte membrane proteins. 4.1R is the prototypical member of the family of 4.1 proteins which are expressed in many cell types besides erythrocytes. The other members of the protein 4.1 family include 4.1N, 4.1G and 4.1B. NHE1 (Na+/H+ exchanger isoform 1) has been reported to be hyperactive in 4.1R-null erythrocytes, supporting a functional interaction between NHE1 and 4.1R. We recently demonstrated that 4.1R binds directly to the cytoplasmic domain of NHE1 (NHE1cd). This interaction involves an EED motif in the 4.1R FERM (4.1/ezrin/radixin/moesin) domain and two clusters of basic amino acids in the NHE1cd, K519R and R556FNKKYVKK, previously shown to mediate PIP2 (phosphatidylinositol 4,5-bisphosphate) binding. The affinity of this interaction is reduced in hypertonic and acidic conditions, demonstrating that this interaction is of electrostatic nature. The binding affinity is also reduced upon binding of Ca2+/CaM (Ca2+-saturated calmodulin) to the 4.1R FERM domain. We propose that 4.1R regulates NHE1 activity through a direct protein-protein interaction that can be modulated by intracellular pH as well as Na+ and Ca2+ concentrations. In this review, we discuss the increasing evidence for an important role for members of the protein 4.1 family of membrane skeletal proteins in the regulation of various ion transporters in erythrocytes and in non-erythroid cells.
    Journal of Proteomics & Bioinformatics 04/2013;
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    ABSTRACT: Protein 4.1G (4.1G) is a widely expressed member of the protein 4.1 family of membrane skeletal proteins. We have previously reported that Ca(2+)-saturated calmodulin (Ca(2+)/CaM) modulates 4.1G interactions with transmembrane and membrane-associated proteins through binding to Four.one-ezrin-radixin-moesin (4.1G FERM) domain and N-terminal headpiece region (GHP). Here we identify a novel mechanism of Ca(2+)/CaM-mediated regulation of 4.1G interactions using a combination of small-angle X-ray scattering, nuclear magnetic resonance spectroscopy, and circular dichroism spectroscopy analyses. We document that GHP intrinsically disordered coiled structure switches to a stable compact structure upon binding of Ca(2+)/CaM. This dramatic conformational change of GHP inhibits in turn 4.1G FERM domain interactions due to steric hindrance. Based upon sequence homologies with the Ca(2+)/CaM-binding motif in protein 4.1R headpiece region, we establish that the 4.1G S(71)RGISRFIPPWLKKQKS peptide (pepG) mediates Ca(2+)/CaM binding. As observed for GHP, the random coiled structure of pepG changes to a relaxed globular shape upon complex formation with Ca(2+)/CaM. The resilient coiled structure of pepG, maintained even in the presence of trifluoroethanol, singles it out from any previously published CaM-binding peptide. Taken together, these results show that Ca(2+)/CaM binding to GHP, and more specifically to pepG, has profound effects on other functional domains of 4.1G.
    Cell biochemistry and biophysics 01/2013; · 3.34 Impact Factor
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    Wataru Nunomura, Masahiko Htakeya, Yuichi Takakuwa
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    ABSTRACT: In human erythrocytes, the 80–kDa isoform of protein 4.1R, 4.1R80, maintains mechanical membrane stability and deformability as a result of multiple protein–protein interactions. 4.1R80 binds to transmembrane proteins glycophorin C (GPC) and band 3 via its 30–kDa N–terminal FERM (Four one–Ezrin–Radixin–Moesin) domain (referred to as “R30” in the present study) and to spectrin and actin via a 10–kDa domain. Although the sites in R30 responsible for interaction with transmembrane proteins have been extensively studied, the identity of these sites has been challenged recently. Antibodies, in particular monoclonal antibodies (mAbs), are powerful tools not only for immunochemical studies but also for functional analyses such as the monitoring of the dynamic interactions of R30 with its binding partners. In the present study, we have generated mouse mAbs against recombinant R30 protein, and characterized their respective recognition epitopes in R30 using various recombinant proteins. Four representative clones, #5, #7, #9, #13 recognized the Y131DPELHGVDYVSDFKLAPN (pep8.1), Q150 TKELEEKVMELHKSYR (pep8.2), M1HCKVSLLDDTVYECVVE (pep4) and Q247EQYESTIGFKLPSYRA (pep13) epitopes, respectively. These sequences are located in the N–,α– and C–lobe structure of R30, respectively. IAsys–based in vitro binding analyses enabled us to demonstrate that the binding of R30 to pH 11–treated inside–out–vesicles (IOVs) was reduced by two combinations of mAbs (#5 and #9 or #7 and #9) but not by any of the mAbs alone and to confirm that the GPC binding site of R30 was located at or near pep8.1 and pep8.2 in the α– lobe of R30. Our study validates that this novel panel of mAbs constitutes a powerful tool for various types of analyses of 4.1R.
    Membrane. 09/2012; 37(5):250-257.
  • Ichiro Koshino, Narla Mohandas, Yuichi Takakuwa
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    ABSTRACT: The membrane skeleton plays a central role in maintaining the elasticity and stability of the erythrocyte membrane, two biophysical features critical for optimal functioning and survival of red cells. Many constituent proteins of the membrane skeleton are phosphorylated by various kinases, and phosphorylation of β-spectrin by casein kinase and of protein 4.1R by PKC has been documented to modulate erythrocyte membrane mechanical stability. In this study, we show that activation of endogenous PKA by cAMP decreases membrane mechanical stability and that this effect is mediated primarily by phosphorylation of dematin. Co-sedimentation assay showed that dematin facilitated interaction between spectrin and F-actin, and phosphorylation of dematin by PKA markedly diminished this activity. Quartz crystal microbalance measurement revealed that purified dematin specifically bound the tail region of the spectrin dimer in a saturable manner with a submicromolar affinity. Pulldown assay using recombinant spectrin fragments showed that dematin, but not phospho-dematin, bound to the tail region of the spectrin dimer. These findings imply that dematin contributes to the maintenance of erythrocyte membrane mechanical stability by facilitating spectrin-actin interaction and that phosphorylation of dematin by PKA can modulate these effects. In this study, we have uncovered a novel functional role for dematin in regulating erythrocyte membrane function.
    Journal of Biological Chemistry 08/2012; 287(42):35244-50. · 4.65 Impact Factor
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    ABSTRACT: NHE1 (Na(+)/H(+) exchanger isoform 1) has been reported to be hyperactive in 4.1R-null erythrocytes [Rivera, De Franceschi, Peters, Gascard, Mohandas and Brugnara (2006) Am. J. Physiol. Cell Physiol. 291, C880-C886], supporting a functional interaction between NHE1 and 4.1R. In the present paper we demonstrate that 4.1R binds directly to the NHE1cd (cytoplasmic domain of NHE1) through the interaction of an EED motif in the 4.1R FERM (4.1/ezrin/radixin/moesin) domain with two clusters of basic amino acids in the NHE1cd, K(519)R and R(556)FNKKYVKK, previously shown to mediate PIP(2) (phosphatidylinositol 4,5-bisphosphate) binding [Aharonovitz, Zaun, Balla, York, Orlowski and Grinstein (2000) J. Cell. Biol. 150, 213-224]. The affinity of this interaction (K(d) = 100-200 nM) is reduced in hypertonic and acidic conditions, demonstrating that this interaction is of an electrostatic nature. The binding affinity is also reduced upon binding of Ca(2+)/CaM (Ca(2+)-saturated calmodulin) to the 4.1R FERM domain. We propose that 4.1R regulates NHE1 activity through a direct protein-protein interaction that can be modulated by intracellular pH and Na(+) and Ca(2+) concentrations.
    Biochemical Journal 06/2012; 446(3):427-35. · 4.65 Impact Factor
  • Daisuke Sasakura, Wataru Nunomura, Yuichi Takakuwa
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    ABSTRACT: Although the 3D structure of the Ca(2+)-bound CaM (Ca(2+)/CaM) complex with the antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide (W-7), has been resolved, the dynamic changes in Ca(2+)/CaM structure upon interaction with W-7 are still unknown. We investigated time- and temperature-dependent dynamic changes in Ca(2+)/CaM interaction with W-7 in physiological conditions using one- and two-dimensional Fourier-transformed infrared spectroscopy (2D-IR). We observed changes in the α-helix secondary structure of Ca(2+)/CaM when complexed with W-7 at a molar ratio of 1:2, but not at higher molar ratios (between 1:2 and 1:5). Kinetic studies revealed that, during the initial 125s at 25°C, Ca(2+)/CaM underwent formation of secondary coil and turn structures upon binding to W-7. Variations in temperature that induced significant changes in the structure of the Ca(2+)/CaM complex failed to do so when Ca(2+)/CaM was complexed with W-7. We concluded that W-7 induced stepwise conformational changes in Ca(2+)/CaM that resulted in a rigidification of the complex and its inability to interact with target proteins and/or polypeptides.
    Biochemical and Biophysical Research Communications 06/2012; 423(2):360-5. · 2.41 Impact Factor
  • Biochemical Journal 04/2012; 443(1):327. · 4.65 Impact Factor
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    Shotaro Tanaka, Yuichi Takakuwa
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    ABSTRACT: Interaction of protein 4.1 (4.1R) with the transmembrane protein glycophorin C (GPC) regulates the functions of erythrocyte membrane. Fluorescence correlation spectroscopy (FCS) was used to define the interaction of EGFP-4.1R with DsRed-GPC on transport vesicles (TVs) by measuring their fluctuation in living cells. DsRed-GPC expressed in HeLa cells was delivered to the plasma membrane through slow vesicle transport. EGFP-4.1R, which freely diffused in the cytosol when expressed alone, diffused slowly when co-expressed with DsRed-GPC, indicating association of EGFP-4.1R with TVs. Fluorescence cross-correlation spectroscopy (FCCS) showed direct interaction of EGFP-4.1R with DsRed-GPC on TVs. The present study demonstrates that 4.1R binds to GPC on TVs in living cells.
    FEBS letters 03/2012; 586(6):668-74. · 3.54 Impact Factor
  • Kohei Shiba, Wataru Nunomura, Yuichi Takakuwa
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    ABSTRACT: In this study, we describe a novel application for light scattering, a method widely used for separation of molecules in solution based on their size. We demonstrate that light scattering analysis can monitor the change in particle size of protein 4.1R prior to and after binding to red blood cell inside-out-vesicles in solution. Light scattering constitutes therefore a novel tool to analyze protein-binding association constants.
    Analytical Sciences 01/2012; 28(6):613-5. · 1.57 Impact Factor
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    ABSTRACT: Mammalian erythroblasts undergo enucleation, a process thought to be similar to cytokinesis. Although an assemblage of actin, non-muscle myosin II, and several other proteins is crucial for proper cytokinesis, the role of non-muscle myosin II in enucleation remains unclear. In this study, we investigated the effect of various cell-division inhibitors on cytokinesis and enucleation. For this purpose, we used human colony-forming unit-erythroid (CFU-E) and mature erythroblasts generated from purified CD34(+) cells as target cells for cytokinesis and enucleation assay, respectively. Here we show that the inhibition of myosin by blebbistatin, an inhibitor of non-muscle myosin II ATPase, blocks both cell division and enucleation, which suggests that non-muscle myosin II plays an essential role not only in cytokinesis but also in enucleation. When the function of non-muscle myosin heavy chain (NMHC) IIA or IIB was inhibited by an exogenous expression of myosin rod fragment, myosin IIA or IIB, each rod fragment blocked the proliferation of CFU-E but only the rod fragment for IIB inhibited the enucleation of mature erythroblasts. These data indicate that NMHC IIB among the isoforms is involved in the enucleation of human erythroblasts.
    Blood 11/2011; 119(4):1036-44. · 9.78 Impact Factor
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    ABSTRACT: In erythrocytes, 4.1R80 (80 kDa isoform of protein 4.1R) binds to the cytoplasmic tail of the transmembrane proteins band 3 and GPC (glycophorin C), and to the membrane-associated protein p55 through the N- (N-terminal), α- (α-helix-rich) and C- (C-terminal) lobes of R30 [N-terminal 30 kDa FERM (4.1/ezrin/radixin/moesin) domain of protein 4.1R] respectively. We have shown previously that R30 binds to CaM (calmodulin) in a Ca2+-independent manner, the equilibrium dissociation constant (Kd) for R30-CaM binding being very similar (in the submicromolar range) in the presence or absence of Ca2+. In the present study, we investigated the consequences of CaM binding on R30's structural stability using resonant mirror detection and FTIR (Fourier-transform IR) spectroscopy. After a 30 min incubation above 40° C, R30 could no longer bind to band 3 or to GPC. In contrast, R30 binding to p55, which could be detected at a temperature as low as 34° C, was maintained up to 44° C in the presence of apo-CaM. Dynamic light scattering measurements indicated that R30, either alone or complexed with apo-CaM, did not aggregate up to 40° C. FTIR spectroscopy revealed that the dramatic variations in the structure of the β-sheet structure of R30 observed at various temperatures were minimized in the presence of apo-CaM. On the basis of Kd values calculated at various temperatures, ΔCp and ΔG° for R30 binding to apo-CaM were determined as -10 kJ · K(-1) · mol-1 and ~ -38 kJ · mol(-1) at 37° C (310.15 K) respectively. These data support the notion that apo-CaM stabilizes R30 through interaction with its β-strand-rich C-lobe and provide a novel function for CaM, i.e. structural stabilization of 4.1R80.
    Biochemical Journal 08/2011; 440(3):367-74. · 4.65 Impact Factor
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    ABSTRACT: The human ether-a-go-go-related gene (hERG) protein is a cardiac potassium channel. Mutations in hERG can result in reductions in membrane channel current, cardiac repolarization, prolongation of QT intervals, and lethal arrhythmia. In the last decade, it has been found that some mutants of hERG involved in long QT syndrome exhibit intracellular protein trafficking defects, while other mutants sort to the membrane but cannot form functional channels. Due to the close relationship between intracellular trafficking and functional protein expression, we aimed to measure differences in protein behavior/motion between wild-type and mutant hERG by directly analyzing the fluorescence fluctuations of green fluorescent protein-labeled proteins using fluorescence correlation spectroscopy (FCS). Our data imply that FCS can be applied as a new diagnostic tool to assess whether the defect in a particular mutant channel protein involves aberrant intracellular trafficking.
    The Journal of Physiological Sciences 05/2011; 61(4):313-9. · 1.09 Impact Factor
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    Wataru Nunomura, Philippe Gascard, Yuichi Takakuwa
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    ABSTRACT: Membrane skeletal protein 4.1R is the prototypical member of a family of four highly paralogous proteins that include 4.1G, 4.1N, and 4.1B. Two isoforms of 4.1R (4.1R(135) and 4.1R(80)), as well as 4.1G, are expressed in erythroblasts during terminal differentiation, but only 4.1R(80) is present in mature erythrocytes. One goal in the field is to better understand the complex regulation of cell type and isoform-specific expression of 4.1 proteins. To start answering these questions, we are studying in depth the important functions of 4.1 proteins in the organization and function of the membrane skeleton in erythrocytes. We have previously reported that the binding profiles of 4.1R(80) and 4.1R(135) to membrane proteins and calmodulin are very different despite the similar structure of the membrane-binding domain of 4.1G and 4.1R(135). We have accumulated evidence for those differences being caused by the N-terminal 209 amino acids headpiece region (HP). Interestingly, the HP region is an unstructured domain. Here we present an overview of the differences and similarities between 4.1 isoforms and paralogs. We also discuss the biological significance of unstructured domains.
    International Journal of Cell Biology 01/2011; 2011:943272.

Publication Stats

2k Citations
301.18 Total Impact Points

Institutions

  • 1998–2014
    • Tokyo Women's Medical University
      • • Department of Biochemistry
      • • Department of Psychiatry
      Edo, Tōkyō, Japan
  • 2013
    • Akita University
      • Center for Geo-Environmental Science
      Akita-shi, Akita-ken, Japan
  • 2002
    • Kyorin University
      Edo, Tōkyō, Japan
    • American Society of Hematology
      Orlando, Florida, United States
  • 1997–1998
    • Lawrence Berkeley National Laboratory
      • Life Sciences Division
      Berkeley, CA, United States
  • 1995–1998
    • Tokyo Junshin Women's College
      • Department of Biochemistry
      Edo, Tōkyō, Japan
  • 1990–1998
    • Hokkaido University Hospital
      • Division of Dermatology
      Sapporo-shi, Hokkaido, Japan
    • University of California, Berkeley
      • Department of Molecular and Cell Biology
      Berkeley, MO, United States
    • Hokkaido University
      • Department of Medicine II
      Sapporo-shi, Hokkaido, Japan
  • 1988–1989
    • University of California, San Francisco
      • Department of Laboratory Medicine
      San Francisco, CA, United States