TY - JOUR TI - The axonal actin-spectrin lattice acts as a tension buffering shock absorber AU - Dubey, Sushil AU - Bhembre, Nishita AU - Bodas, Shivani AU - Veer, Sukh AU - Ghose, Aurnab AU - Callan-Jones, Andrew AU - Pullarkat, Pramod A2 - Sens, Pierre A2 - Akhmanova, Anna VL - 9 PY - 2020 DA - 2020/04/08 SP - e51772 C1 - eLife 2020;9:e51772 DO - 10.7554/eLife.51772 UR - https://doi.org/10.7554/eLife.51772 AB - Axons span extreme distances and are subject to significant stretch deformations during limb movements or sudden head movements, especially during impacts. Yet, axon biomechanics, and its relation to the ultrastructure that allows axons to withstand mechanical stress, is poorly understood. Using a custom developed force apparatus, we demonstrate that chick dorsal root ganglion axons exhibit a tension buffering or strain-softening response, where its steady state elastic modulus decreases with increasing strain. We then explore the contributions from the various cytoskeletal components of the axon to show that the recently discovered membrane-associated actin-spectrin scaffold plays a prominent mechanical role. Finally, using a theoretical model, we argue that the actin-spectrin skeleton acts as an axonal tension buffer by reversibly unfolding repeat domains of the spectrin tetramers to release excess mechanical stress. Our results revise the current viewpoint that microtubules and their associated proteins are the only significant load-bearing elements in axons. KW - axon mechanics KW - spectrin skeleton KW - axonal cytoskeleton JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -