The axonal actin-spectrin lattice acts as a tension buffering shock absorber
- Raman Research Institute, India
- Indian Institute of Science Education and Research, India
- Indian Institute of Science Education and Research, India
- Paris Diderot University, France
Abstract
Axons span extreme distances and are subjected 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 view point that microtubules and their associated proteins are the only significant load-bearing elements in axons.
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All data generated or analysed during this study are included in the manuscript and supporting files.
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Funding
Department of Biotechnology , Ministry of Science and Technology (BT/PR13244/GBD/27/245/2009)
- Pramod Pullarkat
Department of Biotechnology , Ministry of Science and Technology (BT/PR13244/GBD/27/245/2009)
- Aurnab Ghose
Science and Engineering Research Board (EMR/2016/003730)
- Aurnab Ghose
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2020, Dubey et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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The axonal actin-spectrin lattice acts as a tension buffering shock absorber
eLife 9:e51772.
https://doi.org/10.7554/eLife.51772
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