title: Straight GDP-tubulin protofilaments form in the presence of taxol.
abstract: Microtubules exist in dynamic equilibrium, growing and shrinking by the addition or loss of tubulin dimers from the ends of protofilaments. The hydrolysis of GTP in beta-tubulin destabilizes the microtubule lattice by increasing the curvature of protofilaments in the microtubule and putting strain on the lattice. The observation that protofilament curvature depends on GTP hydrolysis suggests that microtubule destabilizers and stabilizers work by modulating the curvature of the microtubule lattice itself. Indeed, the microtubule destabilizer MCAK has been shown to increase the curvature of protofilaments during depolymerization. Here, we show that the atomic force microscopy (AFM) of individual tubulin protofilaments provides sufficient resolution to allow the imaging of single protofilaments in their native environment. By using this assay, we confirm previous results for the effects of GTP hydrolysis and MCAK on the conformation of protofilaments. We go on to show that taxol stabilizes microtubules by straightening the GDP protofilament and slowing down the transition of protofilaments from straight to a curved configuration.
authors.affiliation: Department of Cellular Machines, BioTechnological Center, University of Technology Dresden, Tatzberg 49, D-01307 Dresden, Germany.
authors.forename: Céline
authors.initials: C
authors.lastname: Elie-Caille
authors.forename: Fedor
authors.initials: F
authors.lastname: Severin
authors.forename: Jonne
authors.initials: J
authors.lastname: Helenius
authors.forename: Jonathon
authors.initials: J
authors.lastname: Howard
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Muller
authors.forename: A A
authors.initials: AA
authors.lastname: Hyman
mesh_terms: D000818:Animals; D006153:Guanosine Diphosphate / Q000737:chemistry* / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006868:Hydrolysis; D066298:In Vitro Techniques; D016547:Kinesins / Q000378:metabolism; D018625:Microscopy, Atomic Force; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D046912:Multiprotein Complexes; D017239:Paclitaxel / Q000494:pharmacology*; D011487:Protein Conformation; D021122:Protein Subunits; D014404:Tubulin / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D046912:Multiprotein Complexes; D021122:Protein Subunits; D014404:Tubulin; D006153:Guanosine Diphosphate; D006160:Guanosine Triphosphate; D016547:Kinesins; D017239:Paclitaxel