Nanomechanics of microtubules.

We have determined the mechanical anisotropy of a single microtubule by simultaneously measuring the Young's and the shear moduli in vitro. This was achieved by elastically deforming the microtubule deposited on a substrate tailored by electron-beam lithography with a tip of an atomic force microscope. The shear modulus is 2 orders of magnitude lower than the Young's, giving rise to a length-dependent flexural rigidity of microtubules. The temperature dependence of the microtubule's bending stiffness in the (5-40) degrees C range shows a strong variation upon cooling coming from the increasing interaction between the protofilaments.

[1]  Ph.D. Linda A. Amos B.A.,et al.  Molecules of the Cytoskeleton , 1991, Macmillan Molecular Biology Series.

[2]  E. Nogales,et al.  High-Resolution Model of the Microtubule , 1999, Cell.

[3]  E. Mandelkow,et al.  Microtubule dynamics and microtubule caps: a time-resolved cryo- electron microscopy study , 1991, The Journal of cell biology.

[4]  G. A. D. Briggs,et al.  Elastic and shear moduli of single-walled carbon nanotube ropes , 1999 .

[5]  P. Hansma,et al.  A nondestructive method for determining the spring constant of cantilevers for scanning force microscopy , 1993 .

[6]  D. Murphy,et al.  Kinesin movement on glutaraldehyde-fixed microtubules. , 1996, Analytical biochemistry.

[7]  H Tashiro,et al.  Buckling of a single microtubule by optical trapping forces: direct measurement of microtubule rigidity. , 1995, Cell motility and the cytoskeleton.

[8]  Libchaber,et al.  Buckling microtubules in vesicles. , 1996, Physical review letters.

[9]  Libchaber,et al.  Phase diagram of microtubules. , 1994, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics.

[10]  Yves Engelborghs,et al.  Dynamical and mechanical study of immobilized microtubules with atomic force microscopy , 1996 .

[11]  R. Williams,et al.  Taxol-induced flexibility of microtubules and its reversal by MAP-2 and Tau. , 1993, The Journal of biological chemistry.

[12]  H. Gaub,et al.  Intermolecular forces and energies between ligands and receptors. , 1994, Science.

[13]  J. Howard,et al.  Flexural rigidity of microtubules and actin filaments measured from thermal fluctuations in shape , 1993, The Journal of cell biology.