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BP: Fachverband Biologische Physik

BP 12: Cytoskeleton I

BP 12.3: Vortrag

Dienstag, 10. März 2026, 10:15–10:30, BAR/0205

Beyond the tip: lattice dynamics, seams, and the mechanism of microtubule fracture — •Amir Zablotsky¹, Subham Biswas², Laura Schaedel^2,3, and Karin John¹ — ¹Université Grenoble-Alpes, CNRS, Laboratoire Interdisciplinaire de Physique 38000 Grenoble, France — ²Experimental Physics and Center for Biophysics, Saarland University, 66123 Saarbrücken, Germany — ³PharmaScienceHub (PSH), 66123 Saarbrücken, Germany

The structural integrity of microtubules is paramount for cellular function. While tip behavior has been extensively studied, the dynamics of the microtubule lattice remain less explored. We present a theoretical analysis of lattice fracture mechanisms, focusing on the influence of multi-seam structures arising from monomer defects and aiming to provide a more accurate estimation of GDP lattice parameters.

Our findings reveal that seams function as pre-existing pathways that accelerate damage propagation. Consequently, monomer vacancies destabilize the lattice due to the inherent structural loss of tubulin-tubulin contacts and the additive acceleration of fracture through multiple seams. Furthermore, comparison of our simulations with experiments on lattice fracture suggests that the intrinsic ratio of longitudinal to lateral binding energies is bounded at approximately 1.5, challenging previous predictions of lattice anisotropy from tip-growth models.

These results emphasize the urgent need to revise current microtubule growth models to incorporate parameters obtained from lattice dynamics and reassess their implications for overall microtubule stability and tip dynamics.

Keywords: Microtubule; Lattice defects; Fracture; Kinetic Monte Carlo