1
|
Aihara M, Irie T, Yasukawa K, Minoura I, Miyauchi N, Nishi M, Katayama N, Yachiku K, Jinnouchi H, Kadowaki T, Yamauchi T, Yatomi Y, Kubota N, Sekimizu K. Development of a high-performance liquid chromatographic glycated albumin assay using finger-prick blood samples. Clin Chim Acta 2023; 542:117272. [PMID: 36858193 DOI: 10.1016/j.cca.2023.117272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 02/15/2023] [Accepted: 02/24/2023] [Indexed: 03/02/2023]
Abstract
BACKGROUND Home blood glucose monitoring can be effective for the self-management of diabetic patients. Hemoglobin A1c (HbA1c) is a widely used marker that reflects the average blood glucose within 1-2 months but does not sensitively respond to behavioral changes. Self-monitoring of blood glucose, continuous glucose monitoring, and flush glucose monitoring are sensitive; however, the cost and invasiveness of these tests prevent their widespread use. We focused on glycated albumin (GA), which reflects the average blood glucose levels over 1-2 weeks, and established a GA measurement method for self-sampling, finger-prick blood, which may be submitted for testing through postal service to receive weekly results. METHODS A high-performance liquid chromatography assay was established to measure GA levels in finger-prick blood samples from 103 diabetic patients and the results were compared with venous blood measurements using an enzymatic method. Furthermore, conditions for sending blood samples by mail were evaluated. Under these conditions, samples from 27 healthy and 32 patient volunteers sent through postal service were compared with samples stored in the laboratory. RESULTS GA levels were measured in samples containing > 20 μg albumin, which resulted in a CV less than 0.3%. The correlation between the GA levels of finger-prick blood measured using HPLC and the GA levels of venous blood measured using the enzymatic method was R2 = 0.988 with the slope ∼ 1.0, suggesting that the two were nearly equivalent. GA levels were stable for four days at 30 °C and two days at 37 °C. Mail-delivered samples exhibited a high correlation with samples that were not sent (R2 > 0.99). CONCLUSIONS We established a method to measure GA levels in self-sampled, finger-prick blood sent through postal service in Japan. The method is applicable for weekly feedback of GA levels, which is potentially useful for motivating behavioral changes. In addition to markers such as HbA1c and blood glucose, GA can be used as a marker for assessing dietary and physical activities. This study highlighted the importance of GA monitoring by developing a suitable measurement method for weekly monitoring of GA levels.
Collapse
Affiliation(s)
- Masakazu Aihara
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
| | - Tomoko Irie
- Provigate Inc., University of Tokyo Entrepreneur Plaza, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Keiko Yasukawa
- Department of Clinical Laboratory, The University of Tokyo Hospital, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Itsushi Minoura
- Provigate Inc., University of Tokyo Entrepreneur Plaza, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Noriko Miyauchi
- Provigate Inc., University of Tokyo Entrepreneur Plaza, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Mitsumi Nishi
- Provigate Inc., University of Tokyo Entrepreneur Plaza, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Norikazu Katayama
- Provigate Inc., University of Tokyo Entrepreneur Plaza, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kenji Yachiku
- Provigate Inc., University of Tokyo Entrepreneur Plaza, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hideaki Jinnouchi
- Jinnouchi Hospital, Kuhonji 6-2-3, Chuo-ku, Kumamoto 862-0976, Japan
| | - Takashi Kadowaki
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan; Toranomon Hospital, Toranomon 2-2-2, Minato-ku, Tokyo 105-8470, Japan
| | - Toshimasa Yamauchi
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan
| | - Yutaka Yatomi
- Department of Clinical Laboratory, The University of Tokyo Hospital, Bunkyo-ku, Tokyo 113-8655, Japan
| | - Naoto Kubota
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8655, Japan.
| | - Koshin Sekimizu
- Provigate Inc., University of Tokyo Entrepreneur Plaza, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
| |
Collapse
|
2
|
Ueo H, Ueo H, Minoura I, Gamachi A, Doi T, Yamaguchi M, Yamashita T, Tsuda H, Moriya T, Yamaguchi R, Kozuka Y, Sasaki T, Masuda T, Kai Y, Kubota Y, Urano Y, Mori M, Mimori K. Clinical usefulness of a novel fluorescence technique for the intraoperative diagnosis of surgical margins in patients with breast cancer. Br J Surg 2021; 108:e340-e342. [PMID: 34428279 DOI: 10.1093/bjs/znab265] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/02/2021] [Accepted: 06/22/2021] [Indexed: 11/12/2022]
Abstract
In both 5- and 15-min data, FI was significantly higher in malignant tissues than in benign tissues. The diagnostic accuracy was similar at 5 and 15 min. Therefore, the 5-min FI was enough applying in the further analyses.
Collapse
Affiliation(s)
- H Ueo
- Department of Surgery and Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Ueo Breast Cancer Hospital, Oita, Japan
| | - H Ueo
- Ueo Breast Cancer Hospital, Oita, Japan
| | - I Minoura
- Goryo Chemical, Inc., Sapporo, Japan
| | - A Gamachi
- Department of Pathology, Almeida Memorial Hospital, Oita, Japan
| | - T Doi
- Breast Cancer Centre, Shonan Memorial Hospital, Kamakura, Japan
| | - M Yamaguchi
- Department of Breast Surgery, JCHO Kurume General Hospital, Kurume, Japan
| | - T Yamashita
- Department of Breast and Endocrine Surgery, Kanagawa Cancer Centre, Yokohama, Japan
| | - H Tsuda
- Department of Basic Pathology, National Defence Medical College, Tokorozawa, Japan
| | - T Moriya
- Department of Pathology, Kawasaki Medical School, Kurashiki, Japan
| | - R Yamaguchi
- Department of Pathology and Laboratory Medicine, Kurume University Medical Centre, Kurume, Japan
| | - Y Kozuka
- Department of Pathology, Mie University Hospital, Tsu, Japan
| | - T Sasaki
- Department of Next-Generation Pathology Information and Networking, Faculty of Medicine, The University of Tokyo, Tokyo, Japan
| | - T Masuda
- Department of Surgery, Kyushu University Beppu Hospital, Beppu, Japan
| | - Y Kai
- Ueo Breast Cancer Hospital, Oita, Japan
| | - Y Kubota
- Ueo Breast Cancer Hospital, Oita, Japan
| | - Y Urano
- Graduate School of Medicine and Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - M Mori
- Department of Surgery and Sciences, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - K Mimori
- Department of Surgery, Kyushu University Beppu Hospital, Beppu, Japan
| |
Collapse
|
3
|
Ayukawa R, Iwata S, Imai H, Kamimura S, Hayashi M, Ngo KX, Minoura I, Uchimura S, Makino T, Shirouzu M, Shigematsu H, Sekimoto K, Gigant B, Muto E. GTP-dependent formation of straight tubulin oligomers leads to microtubule nucleation. J Cell Biol 2021; 220:211760. [PMID: 33544140 PMCID: PMC7871348 DOI: 10.1083/jcb.202007033] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 11/23/2020] [Accepted: 01/04/2021] [Indexed: 12/22/2022] Open
Abstract
Nucleation of microtubules (MTs) is essential for cellular activities, but its mechanism is unknown because of the difficulty involved in capturing rare stochastic events in the early stage of polymerization. Here, combining rapid flush negative stain electron microscopy (EM) and kinetic analysis, we demonstrate that the formation of straight oligomers of critical size is essential for nucleation. Both GDP and GTP tubulin form single-stranded oligomers with a broad range of curvatures, but upon nucleation, the curvature distribution of GTP oligomers is shifted to produce a minor population of straight oligomers. With tubulin having the Y222F mutation in the β subunit, the proportion of straight oligomers increases and nucleation accelerates. Our results support a model in which GTP binding generates a minor population of straight oligomers compatible with lateral association and further growth to MTs. This study suggests that cellular factors involved in nucleation promote it via stabilization of straight oligomers.
Collapse
Affiliation(s)
- Rie Ayukawa
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| | - Seigo Iwata
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| | - Hiroshi Imai
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Tokyo, Japan
| | - Shinji Kamimura
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Tokyo, Japan
| | - Masahito Hayashi
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| | - Kien Xuan Ngo
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| | - Itsushi Minoura
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| | - Seiichi Uchimura
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| | - Tsukasa Makino
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| | - Mikako Shirouzu
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | - Hideki Shigematsu
- Laboratory for Protein Functional and Structural Biology, RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | - Ken Sekimoto
- Matière et Systèmes Complexes (MSC), CNRS UMR 7057, Université de Paris, Paris, France.,Gulliver, CNRS UMR 7083, ESPCI Paris and Université Paris Sciences et Lettres, Paris, France
| | - Benoît Gigant
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Etsuko Muto
- Laboratory for Molecular Biophysics, RIKEN Center for Brain Science, Saitama, Japan
| |
Collapse
|
4
|
Minoura I. Towards an understanding of the isotype-specific functions of tubulin in neurons: Technical advances in tubulin expression and purification. Neurosci Res 2017; 122:1-8. [PMID: 28412269 DOI: 10.1016/j.neures.2017.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 03/29/2017] [Accepted: 04/07/2017] [Indexed: 12/20/2022]
Abstract
Microtubules are cytoskeletal filaments critical for determining the complex morphology of neurons, as well as the basic architecture and organization of mitosis in all eukaryotic cells. Microtubules in humans are composed of 8 α- and 9 β-tubulin isotypes, each of which is encoded by different members of a multi-gene family. The expression pattern of tubulin isotypes, in addition to isotype-specific post-translational modifications, is thought to be critical for the morphogenesis of axons and dendrites. Recent studies revealed that several neurodevelopmental disorders are caused by mutations of specific tubulin isotypes, suggesting that each tubulin isotype has distinct functions. Therefore, in vitro and in vivo functional analyses of tubulin isotypes are important to understand the pathogenesis of developmental disorders. Likewise, analysis of developmental disorders may clarify the function of different tubulin isotypes. In this respect, both the preparation of specific tubulin isotypes and of specific mutant tubulin proteins is critical to understanding the function of tubulin. In the last 20 years, various methods have been developed to study functional differences between tubulin isotypes and the functional defects caused by tubulin mutations. These technical achievements have been discussed in this review. The function of tubulin/microtubules in neuronal morphogenesis as revealed through these techniques has also been described.
Collapse
Affiliation(s)
- Itsushi Minoura
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Goryo Chemical Inc., Earee Bldg. 5F, Kita 8 Nishi 18-35-100, Chuo-ku, Sapporo 060-0008, Japan.
| |
Collapse
|
5
|
Minoura I, Takazaki H, Ayukawa R, Saruta C, Hachikubo Y, Uchimura S, Hida T, Kamiguchi H, Shimogori T, Muto E. Reversal of axonal growth defects in an extraocular fibrosis model by engineering the kinesin-microtubule interface. Nat Commun 2016; 7:10058. [PMID: 26775887 PMCID: PMC4735607 DOI: 10.1038/ncomms10058] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Accepted: 10/28/2015] [Indexed: 12/22/2022] Open
Abstract
Mutations in human β3-tubulin (TUBB3) cause an ocular motility disorder termed congenital fibrosis of the extraocular muscles type 3 (CFEOM3). In CFEOM3, the oculomotor nervous system develops abnormally due to impaired axon guidance and maintenance; however, the underlying mechanism linking TUBB3 mutations to axonal growth defects remains unclear. Here, we investigate microtubule (MT)-based motility in vitro using MTs formed with recombinant TUBB3. We find that the disease-associated TUBB3 mutations R262H and R262A impair the motility and ATPase activity of the kinesin motor. Engineering a mutation in the L12 loop of kinesin surprisingly restores a normal level of motility and ATPase activity on MTs carrying the R262A mutation. Moreover, in a CFEOM3 mouse model expressing the same mutation, overexpressing the suppressor mutant kinesin restores axonal growth in vivo. Collectively, these findings establish the critical role of the TUBB3-R262 residue for mediating kinesin interaction, which in turn is required for normal axonal growth and brain development. How mutations in β3-tubulin cause axonal growth defects in congenital fibrosis of the extraocular muscles type 3 remains elusive. Minoura et al. develop a model system using recombinant human tubulin that demonstrates a link between tubulin mutation, impaired kinesin motility and axonal growth defects.
Collapse
Affiliation(s)
- Itsushi Minoura
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroko Takazaki
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Rie Ayukawa
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Chihiro Saruta
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.,Laboratory for Molecular Mechanisms of Thalamus Development, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - You Hachikubo
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Seiichi Uchimura
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tomonobu Hida
- Laboratory for Neuronal Growth Mechanisms, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Kamiguchi
- Laboratory for Neuronal Growth Mechanisms, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Thalamus Development, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Etsuko Muto
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| |
Collapse
|
6
|
Uchimura S, Fujii T, Takazaki H, Ayukawa R, Nishikawa Y, Minoura I, Hachikubo Y, Kurisu G, Sutoh K, Kon T, Namba K, Muto E. A flipped ion pair at the dynein-microtubule interface is critical for dynein motility and ATPase activation. ACTA ACUST UNITED AC 2015; 208:211-22. [PMID: 25583999 PMCID: PMC4298687 DOI: 10.1083/jcb.201407039] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Dynein is a motor protein that moves on microtubules (MTs) using the energy of adenosine triphosphate (ATP) hydrolysis. To understand its motility mechanism, it is crucial to know how the signal of MT binding is transmitted to the ATPase domain to enhance ATP hydrolysis. However, the molecular basis of signal transmission at the dynein-MT interface remains unclear. Scanning mutagenesis of tubulin identified two residues in α-tubulin, R403 and E416, that are critical for ATPase activation and directional movement of dynein. Electron cryomicroscopy and biochemical analyses revealed that these residues form salt bridges with the residues in the dynein MT-binding domain (MTBD) that work in concert to induce registry change in the stalk coiled coil and activate the ATPase. The R403-E3390 salt bridge functions as a switch for this mechanism because of its reversed charge relative to other residues at the interface. This study unveils the structural basis for coupling between MT binding and ATPase activation and implicates the MTBD in the control of directional movement.
Collapse
Affiliation(s)
- Seiichi Uchimura
- Laboratory for Molecular Biophysics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Takashi Fujii
- Graduate School of Frontier Biosciences and Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Kawaguchi, Saitama 332-0012, Japan Quantitative Biology Center, Institute of Physical and Chemical Research, Suita, Osaka 565-0871, Japan
| | - Hiroko Takazaki
- Laboratory for Molecular Biophysics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Rie Ayukawa
- Laboratory for Molecular Biophysics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Yosuke Nishikawa
- Graduate School of Frontier Biosciences and Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Itsushi Minoura
- Laboratory for Molecular Biophysics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - You Hachikubo
- Laboratory for Molecular Biophysics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Genji Kurisu
- Graduate School of Frontier Biosciences and Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Kazuo Sutoh
- Research Institute for Science and Engineering, Waseda University, Toshima-ku, Tokyo 171-0033, Japan
| | - Takahide Kon
- Japan Science and Technology Agency, Precursory Research for Embryonic Science and Technology, Kawaguchi, Saitama 332-0012, Japan Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan Department of Frontier Bioscience, Faculty of Bioscience and Applied Chemistry, Hosei University, Koganei, Tokyo 184-8584, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences and Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan Quantitative Biology Center, Institute of Physical and Chemical Research, Suita, Osaka 565-0871, Japan
| | - Etsuko Muto
- Laboratory for Molecular Biophysics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| |
Collapse
|
7
|
Uchimura S, Fujii T, Takazaki H, Ayukawa R, Nishikawa Y, Minoura I, Hachikubo Y, Kurisu G, Sutoh K, Kon T, Namba K, Muto E. A Mechanical Switch from Diffusion to Directional Motion Activates ATPase in Dynein Motor. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
8
|
Minoura I, Hachikubo Y, Yamakita Y, Takazaki H, Ayukawa R, Uchimura S, Muto E. Overexpression, purification, and functional analysis of recombinant human tubulin dimer. FEBS Lett 2013; 587:3450-5. [PMID: 24021646 DOI: 10.1016/j.febslet.2013.08.032] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/26/2013] [Accepted: 08/26/2013] [Indexed: 12/19/2022]
Abstract
Microtubules consisting of tubulin dimers play essential roles in various cellular functions. Investigating the structure-function relationship of tubulin dimers requires a method to prepare sufficient quantities of recombinant tubulin. To this end, we simultaneously expressed human α1- and β3-tubulin using a baculovirus-insect cell expression system that enabled the purification of 5mg recombinant tubulin per litre of cell culture. The purified recombinant human tubulin could be polymerized into microtubules that glide on a kinesin-coated glass surface. The method provides a powerful tool for in vitro functional analyses of microtubules.
Collapse
Affiliation(s)
- Itsushi Minoura
- Laboratory for Molecular Biophysics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | | | | | | | | | | |
Collapse
|
9
|
Yamakita Y, Hachikubo Y, Ayukawa R, Uchimura S, Muto E, Minoura I. Human Disease-Related Mutation at R262 of β3-Tubulin Critical for Kinesin Motility and ATP Hydrolysis. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
10
|
Minoura I, Degawa M, Ayukawa R, Uchimura S, Sekimoto K, Muto E. KIF1A Repeats Cycle of ‘FREE Diffusion’ and ‘SPECIFIC Binding’ during Weak Binding State. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
11
|
Minoura I, Katayama E, Sekimoto K, Muto E. One-dimensional Brownian motion of charged nanoparticles along microtubules: a model system for weak binding interactions. Biophys J 2010; 98:1589-97. [PMID: 20409479 DOI: 10.1016/j.bpj.2009.12.4323] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2009] [Revised: 12/24/2009] [Accepted: 12/29/2009] [Indexed: 10/19/2022] Open
Abstract
Various proteins are known to exhibit one-dimensional Brownian motion along charged rodlike polymers, such as microtubules (MTs), actin, and DNA. The electrostatic interaction between the proteins and the rodlike polymers appears to be crucial for one-dimensional Brownian motion, although the underlying mechanism has not been fully clarified. We examined the interactions of positively-charged nanoparticles composed of polyacrylamide gels with MTs. These hydrophilic nanoparticles bound to MTs and displayed one-dimensional Brownian motion in a charge-dependent manner, which indicates that nonspecific electrostatic interaction is sufficient for one-dimensional Brownian motion. The diffusion coefficient decreased exponentially with an increasing particle charge (with the exponent being 0.10 kBT per charge), whereas the duration of the interaction increased exponentially (exponent of 0.22 kBT per charge). These results can be explained semiquantitatively if one assumes that a particle repeats a cycle of binding to and movement along an MT until it finally dissociates from the MT. During the movement, a particle is still electrostatically constrained in the potential valley surrounding the MT. This entire process can be described by a three-state model analogous to the Michaelis-Menten scheme, in which the two parameters of the equilibrium constant between binding and movement, and the rate of dissociation from the MT, are derived as a function of the particle charge density. This study highlights the possibility that the weak binding interactions between proteins and rodlike polymers, e.g., MTs, are mediated by a similar, nonspecific charge-dependent mechanism.
Collapse
Affiliation(s)
- Itsushi Minoura
- Laboratory for Molecular Biophysics, Brain Science Institute, RIKEN, Wako, Saitama, Japan.
| | | | | | | |
Collapse
|
12
|
Minoura I, Katayama E, Sekimoto K, Uchimura S, Degawa M, Muto E. Three-State Model for One-Dimensional Brownian Motion of Charged Nanoparticles Along Microtubules. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
13
|
Abstract
Little is known about the electrostatic/dynamic properties of microtubules, which are considered to underlie their electrostatic interactions with various proteins such as motor proteins, microtubule-associated proteins, and microtubules themselves (lateral association of microtubules). To measure the dielectric properties of microtubules, we developed an experiment system in which the electroorientation of microtubules was observed under a dark-field microscope. Upon application of an alternating electric field (0.5-1.9 x 10(5) V/m, 10 kHz-3 MHz), the microtubules were oriented parallel to the field line in a few seconds because of the dipole moment induced along their long axes. The process of this orientation was analyzed based on a dielectric ellipsoid model, and the conductivity and dielectric constant of each microtubule were calculated. The analyses revealed that the microtubules were highly conductive, which is consistent with the counterion polarization model-counterions bound to highly negatively charged microtubules can move along the long axis, and this mobility might be the origin of the high conductivity. Our experiment system provides a useful tool to quantitatively evaluate the polyelectrolyte nature of microtubules, thus paving the way for future studies aiming to understand the physicochemical mechanism underlying the electrostatic interactions of microtubules with various proteins.
Collapse
Affiliation(s)
- Itsushi Minoura
- Brain Developmental Research Group, RIKEN Brain Science Institute, Wako, Japan
| | | |
Collapse
|
14
|
Yagi T, Minoura I, Fujiwara A, Saito R, Yasunaga T, Hirono M, Kamiya R. An axonemal dynein particularly important for flagellar movement at high viscosity. Implications from a new Chlamydomonas mutant deficient in the dynein heavy chain gene DHC9. J Biol Chem 2005; 280:41412-20. [PMID: 16236707 DOI: 10.1074/jbc.m509072200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ciliary and flagellar axonemes contain multiple inner arm dyneins of which the functional difference is largely unknown. In this study, a Chlamydomonas mutant, ida9, lacking inner arm dynein c was isolated and shown to carry a mutation in the DHC9 dynein heavy chain gene. The cDNA sequence of DHC9 was determined, and its information was used to show that >80% of it is lost in the mutant. Electron microscopy and image analysis showed that the ida9 axoneme lacked electron density near the base of the S2 radial spoke, indicating that dynein c localizes to this site. The mutant ida9 swam only slightly slower than the wild type in normal media. However, swimming velocity was greatly reduced when medium viscosity was modestly increased. Thus, dynein c in wild type axonemes must produce a significant force when flagella are beating in viscous media. Because motility analyses in vitro have shown that dynein c is the fastest among all the inner arm dyneins, we can regard this dynein as a fast yet powerful motor.
Collapse
Affiliation(s)
- Toshiki Yagi
- Department of Biological Sciences, University of Tokyo, 7-3-1 Hongo, Tokyo 113-0033, Japan
| | | | | | | | | | | | | |
Collapse
|
15
|
Abstract
The outer doublet microtubules in ciliary and flagellar axonemes are presumed to be connected with each other by elastic links called the inter-doublet links or the nexin links, but it is not known whether there actually are such elastic links. In this study, to detect the elasticity of the putative inter-doublet links, shear force was applied to Chlamydomonas axonemes with a fine glass needle and the longitudinal elasticity was determined from the deflection of the needle. Wild-type axonemes underwent a high-frequency, nanometer-scale vibration in the presence of ATP. When longitudinal shear force was applied, the average position of the needle tip attached to the axoneme moved linearly with the force applied, yielding an estimate of spring constant of 2.0 (S.D.: 0.8) pN/nm for 1 microm of axoneme. This value did not change in the presence of vanadate, i.e., when dynein does not form strong cross bridges. In contrast, it was at least five times larger when ATP was absent, i.e., when dynein forms strong cross bridges. The measured elasticity did not significantly differ in various mutant axonemes lacking the central-pair microtubules, a subset of inner-arm dynein, outer-arm dynein, or the radial spokes, although it was somewhat smaller in the latter two mutants. It was also observed that the shear displacement in an axoneme in the presence of ATP often took place in a stepwise manner. This suggests that the inter-doublet links can reversibly detach from and reattach to the outer doublets in a cooperative manner. This study thus provides the first direct measure of the elasticity of inter-doublet links and also demonstrates its dynamic nature.
Collapse
Affiliation(s)
- I Minoura
- National Institute for Basic Biology, Okazaki, Japan
| | | | | |
Collapse
|
16
|
Abstract
Lobopodium is a hyaline cytoplasmic protrusion which rotates circumferencially around a cell. This movement is called circus movement, which is seen in dissociated cells of amphibian embryos. Relative abundance of the lobopodia-forming cells changes temporally and spatially within Xenopus embryos, reflecting stage-dependent difference of morphogenetic movements. The lobopodia-forming activity of dissociated animal cap cells was stimulated strongly by activin and bFGF, and weakly by TGF-beta 2. In addition, activin A was found to stimulate cellular attachment to the substratum when the cultivation lasted long. Thus, mesoderm-inducing growth factors stimulate lobopodia formation and cellular movements which may be necessary for gastrulation and neurulation in Xenopus early embryos.
Collapse
Affiliation(s)
- I Minoura
- Laboratory of Molecular Embryology, Faculty of Science, University of Tokyo, Japan
| | | | | | | |
Collapse
|
17
|
Minoura I, Kamiya R. Strikingly different propulsive forces generated by different dynein-deficient mutants in viscous media. Cell Motil Cytoskeleton 1995; 31:130-9. [PMID: 7553906 DOI: 10.1002/cm.970310205] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The propulsive force generated by Chlamydomonas mutants deficient in flagellar dynein was estimated from their swimming velocities in viscous media. The force produced by wild-type cells increased by 30-40% when viscosity was raised from 0.9 to 2 cP but decreased as viscosity was further raised above 6 cP. The biphasic dependence of force generation on viscosity was also observed in the mutant ida1, which lacks the I1 component of the inner-arm dynein. The mutant ida4, which lacks the inner-arm I2 component, was extremely susceptible to viscosity and stopped swimming at 6 cP, at which other mutants could swim. In contrast, oda1, which lacks the entire dynein outer arm, produced a fairly constant force of about one-third of the wild-type value, over a viscosity range of 0.9-11 cP. In demembranated and reactivated cell models of the wild type, the propulsive force decreased monotonically as viscosity increased. Thus the increase in force generation at about 2 cP observed in live cells may be caused by some unknown mechanism that is lost in cell models. The cell models of oda1, in contrast, did not show a marked change in force generation with the change in viscosity. These results indicate that the force generation by the outer-arm dynein greatly depends on viscosity or the velocity of movement, whereas the complete set of inner-arm dynein present in the oda1 axoneme produces a fairly constant force at different viscosities. These different properties of inner and outer dynein arms should be important in the mechanism that produces flagellar beating.
Collapse
Affiliation(s)
- I Minoura
- Zoological Institute, Graduate School of Science, University of Tokyo, Japan
| | | |
Collapse
|