Chikako Shingyoji

Izumi Nakano2
Hironori Ueno1
Hideo Higuchi1
Shinji Kamimura1
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The movement of eukaryotic flagella and cilia is regulated by intracellular calcium. We have tested a model in which the central pair of microtubules mediate the effect of Ca(2+) to modify the dynein activity. We used a novel microtubule sliding assay that allowed us to test the effect of Ca(2+) in the presence or absence of the central-pair microtubules.(More)
Although eukaryotic flagella and cilia all share the basic 9+2 microtubule-organization of their internal axonemes, and are capable of generating bending-motion, the waveforms, amplitudes, and velocities of the bending-motions are quite diverse. To explore the structural basis of this functional diversity of flagella and cilia, we here compare the axonemal(More)
Dynein is a microtubule motor that powers motility of cilia and flagella. There is evidence that the relative sliding of the doublet microtubules is due to a conformational change in the motor domain that moves a microtubule bound to the end of an extension known as the stalk. A predominant model for the movement involves a rotation of the head domain, with(More)
Oscillatory movement of eukaryotic flagella is caused by dynein-driven microtubule sliding in the axoneme. The mechanical feedback from the bending itself is involved in the regulation of dynein activity, the main mechanism of which is thought to be switching of the activity of dynein between the two sides of the central pair microtubules. To test this, we(More)
The movement of eukaryotic flagella is characterized by its oscillatory nature. In sea urchin sperm, for example, planar bends are formed in alternating directions at the base of the flagellum and travel toward the tip as continuous waves. The bending is caused by the orchestrated activity of dynein arms to induce patterned sliding between doublet(More)
Flagellar beating is caused by microtubule sliding, driven by the activity of dynein, between adjacent two of the nine doublet microtubules. An essential process in the regulation of dynein is to alternate its activity (switching) between the two sides of the central pair microtubules. The switching of dynein activity can be detected, in an in vitro system(More)
Flagellar movement of the sea urchin sperm is regulated by intracellular Ca(2+). Flagellasialin, a polysialic acid-containing glycoprotein, as well as other membrane proteins seems responsible for the Ca(2+) control. To elucidate the mechanism of Ca(2+) dynamics underlying flagellar movement, we analysed the sperm's mechanosensory behavioural responses by(More)
Zebrafish respond to visual stimuli to adapt their body colour to the background. If, rather than being a simple on/off reaction to visual stimulation, the colour change involves cognitive and memory-related processes, training fish with cyclical changes of the background would be expected to increase its ability to change colour. To test this, we developed(More)
Dynein is a minus-end-directed motor that can generate (forward) force to move along the microtubule toward its minus end. In addition, axonemal dyneins were reported to oscillate in the generation of forward force, and cytoplasmic dynein is observed to generate bidirectional forces in response to defined chemical states. Both dyneins can also respond to(More)
Flagellar and ciliary motility are driven by the activity of dynein, which produces microtubule sliding within the axonemes. Our goal is to understand how dynein motile activity is regulated to produce the characteristic oscillatory movement of flagella. Analysis of various parameters, such as frequency and shear angle in beating flagella, is important for(More)