Axonemal dynein - a natural molecular motor

Biological motor molecules possess many of the characteristics required to power nanomachines. They can generate force and torque, transport specific cargoes over appropriate substrates, and the character and rate of their action can be controlled. In cilia and flagella, axonemal dynein motors are attached to nine microtubule doublets arranged cylindrically around two microtubules. Each motor undergoes a cycle of activity, during which it forms a transient attachment to the neighbouring doublet, and pushes it towards the tip of the cilium or flagellum. Dynein motors have been isolated, deposited on a glass slide, and reactivated by adenosine triphosphate. Under these in vitro conditions, assemblies of these motors can propel microtubules across the slide with velocities that are found to increase with microtubule length. Computer simulations have been developed to predict these velocities. Simulations allow us to investigate individual motor properties in addition to characterizing the coordination of activity within the assembly. Agreement between experiment and simulation results from random or sequential activity within the motor assembly and motility characteristics of an individual arm are thus predicted. The sliding which occurs when microtubules are extruded from disintegrating cilia and flagella has also been simulated to enable in vivo characteristics of dynein to be studied.

[1]  R. Vale,et al.  Rotation and translocation of microtubules in vitro induced by dyneins from Tetrahymena cilia , 1988, Cell.

[2]  M. Holwill,et al.  Mechanochemical aspects of axonemal dynein activity studied by in vitro microtubule translocation. , 1995, Biophysical journal.

[3]  R. Kamiya,et al.  Microtubule sliding in mutant Chlamydomonas axonemes devoid of outer or inner dynein arms , 1986, The Journal of cell biology.

[4]  M. Holwill,et al.  Biophysical aspects and modelling of ciliary motility. , 1995, Cell motility and the cytoskeleton.

[5]  Toshio Yanagida,et al.  Dynein arms are oscillating force generators , 1998, Nature.

[6]  J. Spudich,et al.  Myosin step size. Estimation from slow sliding movement of actin over low densities of heavy meromyosin. , 1990, Journal of molecular biology.

[7]  R. Kamiya,et al.  Translocation and rotation of microtubules caused by multiple species of Chlamydomonas inner-arm dynein , 1992 .

[8]  Y. Toyoshima,et al.  Length dependence of displacement fluctuations and velocity in microtubule sliding movement driven by sea urchin sperm outer arm beta dynein in vitro. , 1997, Biophysical chemistry.

[9]  E. Kurimoto,et al.  Microtubule sliding in flagellar axonemes of Chlamydomonas mutants missing inner- or outer-arm dynein: velocity measurements on new types of mutants by an improved method. , 1991, Cell motility and the cytoskeleton.

[10]  C. Omoto,et al.  Activation of the dynein adenosinetriphosphatase by microtubules. , 1986, Biochemistry.

[11]  Christoph F. Schmidt,et al.  Direct observation of kinesin stepping by optical trapping interferometry , 1993, Nature.

[12]  M. Holwill,et al.  Assessment of inner dynein arm structure and possible function in ciliary and flagellar axonemes. , 1999, Cell motility and the cytoskeleton.

[13]  W. Sale,et al.  Direction of active sliding of microtubules in Tetrahymena cilia. , 1977, Proceedings of the National Academy of Sciences of the United States of America.

[14]  M. Holwill,et al.  Computer modelling of Tetrahymena axonemes at macromolecular resolution. Interpretation of electron micrographs. , 1991, Journal of cell science.