Calcium Regulation of an Actin Spring
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Tam-2009-Calcium Regulation o.pdf
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Author(s)
Tam, Barney K.
Shin, Jennifer H.
Pfeiffer, Emily
Mahadevan, L.
Matsudaira, Paul T.
Date Issued
August 2009
Journal
Biophysical Journal
Publisher
Elsevier
Citation
Tam, Barney K., Jennifer H. Shin, Emily Pfeiffer, P. Matsudaira, and L. Mahadevan. “Calcium Regulation of an Actin Spring.” Biophysical Journal 97, no. 4 (August 2009): 1125–1129. © 2009 Biophysical Society
Version
Final published version
Abstract
Calcium is essential for many biological processes involved in cellular motility. However, the pathway by which calcium influences motility, in processes such as muscle contraction and neuronal growth, is often indirect and complex. We establish a simple and direct mechanochemical link that shows how calcium quantitatively regulates the dynamics of a primitive motile system, the actin-based acrosomal bundle of horseshoe crab sperm. The extension of this bundle requires the continuous presence of external calcium. Furthermore, the extension rate increases with calcium concentration, but at a given concentration, we find that the volumetric rate of extension is constant. Our experiments and theory suggest that calcium sequentially binds to calmodulin molecules decorating the actin filaments. This binding leads to a collective wave of untwisting of the actin filaments that drives bundle extension.
MIT Department
Massachusetts Institute of Technology. Department of Biological Engineering
Massachusetts Institute of Technology. Department of Biology
Massachusetts Institute of Technology. Department of Physics
Whitehead Institute for Biomedical Research
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1016/j.bpj.2009.02.069
