Structural transitions in the GTP cap visualized by cryo-electron microscopy of catalytically inactive microtubules.

ABSTRACT: Microtubules (MTs) are polymers of αβ-tubulin heterodimers that stochastically switch between growth and shrinkage phases. This dynamic instability is critically important for MT function. It is believed that GTP hydrolysis within the MT lattice is accompanied by destabilizing conformational changes and that MT stability depends on a transiently existing GTP cap at the growing MT end. Here, we use cryo-electron microscopy and total internal reflection fluorescence microscopy of GTP hydrolysis-deficient MTs assembled from mutant recombinant human tubulin to investigate the structure of a GTP-bound MT lattice. We find that the GTP-MT lattice of two mutants in which the catalytically active glutamate in α-tubulin was substituted by inactive amino acids (E254A and E254N) is remarkably plastic.

SUBMITTER: LaFrance BJ 

PROVIDER: S-EPMC8764682 | biostudies-literature | 2022 Jan

REPOSITORIES: biostudies-literature