Document Type



Bundling of rapidly polymerizing actin filaments underlies dynamics of filopodial protrusions that play an important role in cell migration and cell-cell interaction. Recently, formation of actin bundles has been reconstituted in vitro and two scenarios of bundle initiation, involving binding of two filament tips and, alternatively, linking of the tip of one filament to the side of the other, -have been discussed. A first theoretical analysis is presented indicating that the two mechanisms can be distinguished experimentally. While both of them result counter-intuitively in comparable numbers of bundles, these numbers scale differently with the average bundle length. We propose an experiment for determining which of the two mechanisms is involved in the in vitro bundle formation.


Phys Rev Lett. Author manuscript; available in PMC 2009 April 14. Published in final edited form as: Phys Rev Lett. 2008 September 19; 101(12): 128102. Published online 2008 September 17. PMCID: PMC2668770 NIHMSID: NIHMS96624