The Sindelar lab recently refined a 3D cryo-EM method that allows for better understanding of the structural origins of microtubule flexibility and dynamics. Tubular polymers play essential roles in various cellular activities, and while structures of microtubules have been captured by cryo-EM, determining structurally the dynamic properties of these microtubules has been limited by existing refinement methods. In their recent paper, the Sindelar proposes a new method of refinement that enhanced the 3D cryo-EM reconstruction to a resolution that allows for the observation of the structural properties involved in microtubule dynamics.
Using this new method of refinement, the Sindelar lab was able to capture asymmetric fluctuations in microtubule walls. Surprisingly, they show that microtubule geometry frequently deviates from helical symmetry at the microtubule seam. These varying geometries are associated with different tubulin M-loop conformations and microtubule wall dynamics. This structural insight into microtubule dynamics is the first of many made possible with this novel 3D cryo-EM refinement method.
Read the paper here: https://doi.org/10.1073/pnas.2001546117
By: Jake Thrasher