Brokaw, Charles J. (2002) Computer Simulation of Flagellar Movement VIII: Coordination of Dynein by Local Curvature Control Can Generate Helical Bending Waves. Cell Motility and the Cytoskeleton, 53 (2). pp. 103-124. ISSN 0886-1544. http://resolver.caltech.edu/CaltechAUTHORS:20120212-114928851
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Computer simulations have been carried out with a model flagellumthat can bend in three dimensions. A pattern of dynein activation in which regions of dynein activity propagate along each doublet, with a phase shift of approximately 1/9 wavelength between adjacent doublets, will produce a helical bending wave. This pattern can be termed “doublet metachronism.” The simulations showthat doublet metachronismcan arise spontaneously in a model axoneme in which activation of dyneins is controlled locally by the curvature of each outer doublet microtubule. In this model, dyneins operate both as sensors of curvature and as motors. Doublet metachronism and the chirality of the resulting helical bending pattern are regulated by the angular difference between the direction of the moment and sliding produced by dyneins on a doublet and the direction of the controlling curvature for that doublet. A flagellum that is generating a helical bending wave experiences twisting moments when it moves against external viscous resistance. At high viscosities, helical bending will be significantly modified by twist unless the twist resistance is greater than previously estimated. Spontaneous doublet metachronismmust be modified or overridden in order for a flagellumto generate the planar bending waves that are required for efficient propulsion of spermatozoa. Planar bending can be achieved with the three-dimensional flagellar model by appropriate specification of the direction of the controlling curvature for each doublet. However, experimental observations indicate that this “hard-wired” solution is not appropriate for real flagella.
|Additional Information:||© 2002 Wiley-Liss, Inc. Received 11 March 2002; Accepted 3 May 2002. Article first published online: 27 Aug. 2002. I thank Dr. C.K. Omoto for valuable comments on an early version of this manuscript.|
|Subject Keywords:||cilia; flagella; helix; motility; spermatozoa; writhe|
|Official Citation:||Brokaw, C. J. (2002), Computer simulation of flagellar movement VIII: Coordination of dynein by local curvature control can generate helical bending waves. Cell Motility and the Cytoskeleton, 53: 103–124. doi: 10.1002/cm.10067|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Charles Brokaw|
|Deposited On:||13 Feb 2012 15:39|
|Last Modified:||13 Feb 2012 15:39|
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