Profilin and formin constitute a pacemaker system for robust actin filament growth
- Max Planck Institute of Molecular Physiology, Germany
- Institut Curie, France
- TU Dortmund University, Germany
Abstract
The actin cytoskeleton drives many essential biological processes, from cell morphogenesis to motility. Assembly of functional actin networks requires control over the speed at which actin filaments grow. How this can be achieved at the high and variable levels of soluble actin subunits found in cells is unclear. Here we reconstitute assembly of mammalian, non-muscle actin filaments from physiological concentrations of profilin-actin. We discover that under these conditions, filament growth is limited by profilin dissociating from the filament end and the speed of elongation becomes insensitive to the concentration of soluble subunits. Profilin release can be directly promoted by formin actin polymerases even at saturating profilin-actin concentrations. We demonstrate that mammalian cells indeed operate at the limit to actin filament growth imposed by profilin and formins. Our results reveal how synergy between profilin and formins generates robust filament growth rates that are resilient to changes in the soluble subunit concentration.
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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
Human Frontier Science Program (CDA00070/2017-2)
- Johanna Funk
- Peter Bieling
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2019, Funk 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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Profilin and formin constitute a pacemaker system for robust actin filament growth
eLife 8:e50963.
https://doi.org/10.7554/eLife.50963
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