A5061591035- Microtubule and mitosis dynamics
- Micro and Nano Robotics
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Protist diversity and phylogeny
- Photosynthetic Processes and Mechanisms
- Genetic and Kidney Cyst Diseases
- Crystallography and molecular interactions
- Microfluidic and Bio-sensing Technologies
- Cephalopods and Marine Biology
- Magnetic and Electromagnetic Effects
- Orbital Angular Momentum in Optics
- Electrostatics and Colloid Interactions
- Coleoptera Taxonomy and Distribution
- Spectroscopy and Quantum Chemical Studies
- Sperm and Testicular Function
- Cancer Treatment and Pharmacology
- Cellular Mechanics and Interactions
- 14-3-3 protein interactions
- DNA and Nucleic Acid Chemistry
- Photoreceptor and optogenetics research
- Plant and animal studies
- Neurobiology and Insect Physiology Research
- Insect and Arachnid Ecology and Behavior
- Force Microscopy Techniques and Applications
Chuo University
2015-2025
The University of Tokyo
2001-2012
Tokyo University of the Arts
1989-2012
Toho University
2009-2011
Florida State University
1999
Max Planck Unit for Structural Molecular Biology
1992
ARCH Development Corporation
1985
Tokyo Zoological Park Society
1981-1982
Tokyo University of Science
1981
Kinesin-1, the founding member of kinesin superfamily proteins, is known to use only a subset microtubules for transport in living cells. This biased proposed as guidance cue polarized neurons, but underlying mechanisms are still poorly understood. Here, we report that kinesin-1 binding changes microtubule lattice and promotes further binding. high-affinity state requires nucleotide-free state. Microtubules return initial low-affinity by washing out or non-hydrolyzable ATP analogue AMPPNP...
Paclitaxel (Taxol) is a taxane and chemotherapeutic drug that stabilizes microtubules. While the interaction of paclitaxel with microtubules well described, lack high-resolution structural information on tubulin-taxane complex precludes comprehensive description binding determinants affect its mechanism action. Here, we solved crystal structure baccatin III core moiety paclitaxel-tubulin at 1.9 Å resolution. Based this information, engineered taxanes modified C13 side chains, their...
Microtubules (MTs) are hollow cylinders made of tubulin, a GTPase responsible for essential functions during cell growth and division, thus, key target anti-tumor drugs. In MTs, GTP hydrolysis triggers structural changes in the lattice, which interaction with regulatory factors. The stabilizing GTP-cap is hallmark MTs mechanism chemical-structural link between site MT lattice matter debate. We have analyzed structure tubulin assembled presence fluoride salts that mimic GTP-bound GDP•Pi...
Nucleation of microtubules (MTs) is essential for cellular activities, but its mechanism unknown because the difficulty involved in capturing rare stochastic events early stage polymerization. Here, combining rapid flush negative stain electron microscopy (EM) and kinetic analysis, we demonstrate that formation straight oligomers critical size nucleation. Both GDP GTP tubulin form single-stranded with a broad range curvatures, upon nucleation, curvature distribution shifted to produce minor...
ABSTRACT Dyneins are huge motor protein complexes that essential for cell motility, division, and intracellular transport. classified into three major subfamilies, namely cytoplasmic, intraflagellar‐transport (IFT), ciliary dyneins, based on their localization functions. Recently, several near‐atomic resolution structures have been reported cytoplasmic/IFT dyneins. In contrast, the of as well regulatory mechanisms, yet to be fully elucidated. Here, we isolated a heterodimeric dynein...
A novel method has been developed to measure nanometric displacement under a conventional optical microscope. The magnified image of pinhole was divided into two parts using prism-shaped mirror. difference light intensity between the images determined, which proportional displacementof pinhole. Using 5-microm diam pinhole, accuracy determine ~1 nm. Instead polystyrene microbeads were used in new method. Displacement also measured with accuracy. This technique could be probe phenomena microscopes.
Flagellar axonemes of sea urchin sperm display high-frequency (approximately 300 Hz) vibration with nanometer-scale amplitudes in the presence ATP (Kamimura, S., and R. Kamiya. 1989. Nature (Lond.). 340:476-478). The appears to represent normal mechanochemical interaction between dynein microtubules because dependence frequency on MgATP concentration is similar that axonemal motility, it inhibited by micromolar concentrations vanadate. In this study a two-dimensional photo-sensor was used...
SUMMARY Increased intracellular pH ([pH]i) activates dynein in sea urchin and mammalian sperm induces activation of flagellar motility. It is thought that cAMP-dependent protein phosphorylation associated with motility through increasing [pH]i, but little attention has been given to the cAMP-independent also induced by the[pH]i increase. The present study demonstrates increase in[pH]i starfish axonemal proteins independently cAMP. Flagellar intact was activated when [pH]i raised addition...
Microtubules are key components of the cytoskeleton in eukaryotic cells. The dynamics between assembled microtubules and free tubulin dimers cytoplasm is closely related to active shape changes microtubule networks. One most fundamental questions association with molecular conformation within microtubules. To address this issue, we applied a new technique for rapid shear-flow alignment biological filaments, enabling us acquire structural periodicity data by X-ray fiber diffraction under...
Microtubules are built of tubulin subunits assembled into hollow cylinders which consist parallel protofilaments. Thus, motor molecules interacting with a microtubule could do so either one or several subunits. This makes it difficult to determine the structural requirements for interaction. One way approach problem is alter surface lattice. can be done in ways. Proto-filaments exposed on their inside (C-tubules "sheets"), they made antiparallel (zinc sheets), rolled up (duplex tubules). We...
In the present study, we demonstrated that mouse embryonic stem cells were differentiated into ciliated epithelial cells, with characteristics of normal cells. These expressed ciliary marker proteins, such as β‐tubulin IV and hepatocyte nuclear factor‐3/forkhead homolog 4 (HFH‐4), processed microtubules arranged in 9 + 2 structure, which is same specific alignment observed microtubules. The cilia these beating at a frequency 17–20 Hz. embryoid bodies (EBs) containing respiratory genes...
For the conservation of diving beetle Dytiscus sharpi (Wehncke) (Coleoptera: Dytiscidae), which is included on Red Data List Japan, it critical to understand its ecological background. In present study, we focused feeding behavior and nutritional needs under laboratory breeding conditions. First, made a list possible candidates prey in same habitats where caught D. sharpi. We found that tadpoles Rana ornativentris (Werner) were major species from March April, when larvae appeared. Second,...
In sea-urchin spermatozoa, energy required for flagellar motility is provided by ATP diffusion from mitochondria located at the proximal ends of flagella along with creatine shuttle system. However, no direct analysis rates inside has been carried out thus far. Using a FRAP (fluorescence recovery after photobleaching) technique, we determined coefficients fluorescein-derivatives (calcein, carboxyfluorescein and Oregon Green) to be 63-64 microm2 s(-1). Although these values are about one...
Abstract Flagellar axonemes of sea urchin sperm display high frequency (200–400 Hz) vibration with nanometer scale amplitudes in the presence ATP [Kamimura and Kamiya, 1992: J. Cell Biol. 116:1443–1454]. To investigate how various axonemal components affect vibration, we examined wild‐type mutant Chlamydomonas . At 1 mM ATP, underwent at 100–650 Hz 4–40 nm. This was similar to, but less regular than, that sperm. Axonemes mutants ida 4 lacking part inner arm dynein vibrations...
For conservation purposes and to supply rare insects for laboratory use, a system artificial breeding is crucial. However, in the case of carnivorous freshwater such as diving beetles, constant conditions aquariums are difficult maintain due their high rate food consumption. Furthermore, surface rippling caused by pumping water circulation hinders respiration small larvae. We developed new open aquarium without that was successfully applied rearing larvae Dytiscus sharpi (Wehncke)...
We have devised a novel method to visualize the fluorescence spectrum of single fluorescent molecule using prism‐based spectroscopy. Equiping total internal reflection microscope with newly designed wedge prism, we obtained spectral image rhodamine red attached an essential light chain myosin. also single‐pair resonance energy transfer between and Cy5 in double‐labeled myosin motor domain. This could become useful tool investigate dynamic processes biomolecules at single‐molecule level.