The lattice as allosteric effector: structural studies of alphabeta- and gamma-tubulin clarify the role of GTP in microtubule assembly.

ABSTRACT: GTP-dependent microtubule polymerization dynamics are required for cell division and are accompanied by domain rearrangements in the polymerizing subunit, alphabeta-tubulin. Two opposing models describe the role of GTP and its relationship to conformational change in alphabeta-tubulin. The allosteric model posits that unpolymerized alphabeta-tubulin adopts a more polymerization-competent conformation upon GTP binding. The lattice model posits that conformational changes occur only upon recruitment into the growing lattice. Published data support a lattice model, but are largely indirect and so the allosteric model has prevailed. We present two independent solution probes of the conformation of alphabeta-tubulin, the 2.3 A crystal structure of gamma-tubulin bound to GDP, and kinetic simulat

SUBMITTER: Rice LM 

PROVIDER: S-EPMC2291134 | biostudies-literature | 2008 Apr

REPOSITORIES: biostudies-literature