title: Microtubule treadmills--possible molecular machinery.
abstract: Microtubule polymerization in vitro is the summation of different reactions occurring at each end of the polymer. In steady-state conditions in vitro, net tubulin addition on the microtubule occurs at one end of the polymer, and net tubulin loss occurs at the opposite end. Thus, a unidirectional flux of tubulin from one end of the microtubule to the other, or "treadmilling', can occur. The opposite end assembly--disassembly behaviour of microtubules, if it occurs within cells, could be fundamentally linked to the functions of microtubules, as, for example, in the translocation of chromosomes during mitosis.
mesh_terms: D000199:Actins / Q000502:physiology; D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D002465:Cell Movement; D003599:Cytoskeleton / Q000502:physiology; D005057:Eukaryotic Cells / Q000502:physiology; D066298:In Vitro Techniques; D008870:Microtubules / Q000187:drug effects / Q000502:physiology*; D008938:Mitosis; D011485:Protein Binding; D014404:Tubulin / Q000502:physiology*
chemical_list: D000199:Actins; D014404:Tubulin