Thermal fluctuations of grafted microtubules provide evidence of a length-dependent persistence length
We find that microtubules, essential structural elements in living cells, grow stiffer as they grow longer, an unexpected property that could lead to advances in nano-materials development.
Microtubules, which are about 25 nanometers in diameter, play an essential role in many cellular processes, acting as girders of support for the cell and tracks along which organelles can move. They are also essential components of flagella and cilia, the extensions of some cells that give them movement. Using single particle tracking techniques the stiffness and length of cellular microtubules has been measured. The microtubules' unique properties are attributed to their biological construction. The nanometer-sized filaments are hollow tubes made of tubulin proteins that bind to each other in ways that give them the ability to be both flexible and stiff. Flexibility is important for microtubules as they grow and change in cells, while rigidity is important when cells need support. The microtubules' properties, and the ability to measure them using single-particle tracking, could provide new insights into using the filaments as models for the development of nano-materials.