title: Conformational changes in tubulin in GMPCPP and GDP-taxol microtubules observed by cryoelectron microscopy.
abstract: Microtubules are dynamic polymers that stochastically switch between growing and shrinking phases. Microtubule dynamics are regulated by guanosine triphosphate (GTP) hydrolysis by β-tubulin, but the mechanism of this regulation remains elusive because high-resolution microtubule structures have only been revealed for the guanosine diphosphate (GDP) state. In this paper, we solved the cryoelectron microscopy (cryo-EM) structure of microtubule stabilized with a GTP analogue, guanylyl 5'-α,β-methylenediphosphonate (GMPCPP), at 8.8-Å resolution by developing a novel cryo-EM image reconstruction algorithm. In contrast to the crystal structures of GTP-bound tubulin relatives such as γ-tubulin and bacterial tubulins, significant changes were detected between GMPCPP and GDP-taxol microtubules at the contacts between tubulins both along the protofilament and between neighboring protofilaments, contributing to the stability of the microtubule. These findings are consistent with the structural plasticity or lattice model and suggest the structural basis not only for the regulatory mechanism of microtubule dynamics but also for the recognition of the nucleotide state of the microtubule by several microtubule-binding proteins, such as EB1 or kinesin.
authors.affiliation: Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Yajima
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Ogura
authors.forename: Ryo
authors.initials: R
authors.lastname: Nitta
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Okada
authors.forename: Chikara
authors.initials: C
authors.lastname: Sato
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Hirokawa
mesh_terms: D000465:Algorithms; D000818:Animals; D001921:Brain / Q000378:metabolism; D020285:Cryoelectron Microscopy / Q000379:methods*; D006153:Guanosine Diphosphate / Q000737:chemistry; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000737:chemistry*; D006868:Hydrolysis; D007091:Image Processing, Computer-Assisted; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008968:Molecular Conformation; D017239:Paclitaxel / Q000737:chemistry; D011487:Protein Conformation; D013269:Stochastic Processes; D013552:Swine; D014404:Tubulin / Q000737:chemistry
chemical_list: D014404:Tubulin; D006153:Guanosine Diphosphate; C004805:5'-guanylylmethylenebisphosphonate; D006160:Guanosine Triphosphate; D017239:Paclitaxel