Inter-filament attractions narrow the length distribution of actin filaments

Abstract

We show that the exponential length distribution that is typical ofactin filaments under physiological conditions dramatically narrowsin the presence of i) crosslinker proteins or ii) polyvalentcounterions or iii) depletion-mediated attractions. A simpletheoretical model shows that, at equilibrium, short-rangeattractions that are known to enhance the tendency of filaments toalign parallel to each other, lead to an increase in the averagefilament length and a decrease in the relative width of thedistribution of filament lengths.