Phase changes at the end of a microtubule with a GTP cap.
Examination of Monte Carlo kinetic simulations, based on a realistic set of microscopic rate constants that apply to the end of a microtubule with a GTP cap, suggests that the end of a microtubule alternates between two quasimacroscopic phases. In one phase, the microtubule end has a GTP cap that fluctuates in size; in the other phase, the GTP cap has been lost. These repeated phase changes take place at any given tubulin concentration in a wide range of concentrations. While in the first phase, the microtubule grows slowly; while in the second phase, it shortens rapidly and may disappear completely. These results are closely related to the recent experimental work of Mitchison and Kirschner [Mitchison, T. & Kirschner, M.W. (1984) Nature (London), in press].
D000818:Animals; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007700:Kinetics; D008433:Mathematics; D008870:Microtubules / Q000648:ultrastructure*; D008954:Models, Biological; D011485:Protein Binding; D014404:Tubulin / Q000378:metabolism*
D014404:Tubulin; D006160:Guanosine Triphosphate