Characterization of microtubules buckling in living cell

CARLA PALLAVICINI; ALEJANDRO MONASTRA; NICOLÁS GONZALEZ BARDECI; DIANA WETZLER; VALERIA LEVI; LUCIANA BRUNO

EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS

SPRINGER

Lugar: Berlin; Año: 2017

0175-7571

Microtubules are filamentous biopolymersinvolved in essential biological processes. They form keystructures in eukaryotic cells, and thus it is very importantto determine the mechanisms involved in the formationand maintenance of the microtubule network. Microtubulebucklings are transient and localized events commonlyobserved in living cells and characterized by a fast bendingand its posterior relaxation. Active forces provided bymolecular motors have been indicated as responsible formost of these rapid deformations. However, the factorsthat control the shape amplitude and the time scales of therising and release stages remain unexplored. In this work,we study microtubule buckling in living cells using Xenopuslaevis melanophores as a model system. We trackedsingle fluorescent microtubules from high temporal resolution(0.3?2 s) confocal movies. We recovered the centercoordinates of the filaments with 10-nm precision and analyzed the amplitude of the deformation as a functionof time. Using numerical simulations, we explored differentforce mechanisms resulting in microtubule bending.The simulated events reproduce many features observedfor microtubules, suggesting that a mechanistic modelcaptures the essential processes underlying microtubulebuckling. Also, we studied the interplay between activelytransported vesicles and the microtubule network using atwo-color technique. Our results suggest that microtubulesmay affect transport indirectly besides serving as tracks ofmotor-driven organelles. For example, they could obstructorganelles at microtubule intersections or push them duringfilament mechanical relaxation.