Citation: Valentin Wössner, Falko Ziebert, Ulrich S. Schwarz (2025).
Link: Zotero
Summary
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Key finding: While studies have investigated diffusion-limited growth in lamellipodia and bead assays, Wossner et al. note a gap: previous work had not considered the role of local monomer depletion in enabling coexistence among multiple competing structures.
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Method:
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Limitations:
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Notes in my words:
- Multiple bead assays have competition for limited pool of actin monomers.
- For multiple structures to coexist, a constant turnover of actin monomer supply is required.
- “Weaker structures” (the ones with higher critical concentrations) may shrink or entirely deplete as the “stronger structures” (the ones with low critical concentrations) use up all the available actin from the limited pool.
Results:
The scaling of the monomer concentration in the branching zone with ∼ 1/(1 + n) can be seen in Fig. 2(b). By distinguishing between the global depletion of monomers via G(n) and the local depletion caused by the factor 1/(1 + n), we see that local depletion is the dominating effect, meaning that the growth of a network is diffusion-limited long before the global concentration would reach the critical concentration.
Relevance to my research
- Directly relevant
- Background
- Methods
Quotes / Figures
Important quotes/figures here
Author's contribution to the existing literature:
here we propose local depletion of actin monomers at the leading edge of a dense network as a naturally arising negative feedback between the current state of a structure (filament density) and its growth rate (creation of new branches), and therefore as a mechanism for the coexistence of networks observed in the bead motility assay.
Limited pool models to how the size of dynamic structures in the cell is controlled/maintained/affected when there’s a limited supply of actin monomers:
- Amount of available monomers is not enough to explain (predict?) the size of the actin structures
- Limited pool models need to be extended to ‘size-sensitive mechanisms’ @banerjeeSizeRegulationMultiple2022