title: A thermodynamic model of microtubule assembly and disassembly.
abstract: Microtubules are self-assembling polymers whose dynamics are essential for the normal function of cellular processes including chromosome separation and cytokinesis. Therefore understanding what factors effect microtubule growth is fundamental to our understanding of the control of microtubule based processes. An important factor that determines the status of a microtubule, whether it is growing or shrinking, is the length of the GTP tubulin microtubule cap. Here, we derive a Monte Carlo model of the assembly and disassembly of microtubules. We use thermodynamic laws to reduce the number of parameters of our model and, in particular, we take into account the contribution of water to the entropy of the system. We fit all parameters of the model from published experimental data using the GTP tubulin dimer attachment rate and the lateral and longitudinal binding energies of GTP and GDP tubulin dimers at both ends. Also we calculate and incorporate the GTP hydrolysis rate. We have applied our model and can mimic published experimental data, which formerly suggested a single layer GTP tubulin dimer microtubule cap, to show that these data demonstrate that the GTP cap can fluctuate and can be several microns long.
authors: Biophysical Sciences Institute, University of Durham, Durham, UK. b.m.a.g.piette@durham.ac.uk
authors: Bernard M A G
authors: BM
authors: Piette
authors: Junli
authors: J
authors: Liu
authors: Kasper
authors: K
authors: Peeters
authors: Andrei
authors: A
authors: Smertenko
authors: Timothy
authors: T
authors: Hawkins
authors: Michael
authors: M
authors: Deeks
authors: Roy
authors: R
authors: Quinlan
authors: Wojciech J
authors: WJ
authors: Zakrzewski
authors: Patrick J
authors: PJ
authors: Hussey
mesh_terms: D001665:Binding Sites; D019281:Dimerization; D006153:Guanosine Diphosphate / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D008870:Microtubules / Q000378:metabolism*; D009010:Monte Carlo Method; D013816:Thermodynamics; D014404:Tubulin / Q000378:metabolism
chemical_list: D014404:Tubulin; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate