PT  - JOURNAL ARTICLE
AU  - Alvaro H. Crevenna
AU  - Marcelino Arciniega
AU  - Aurélie Dupont
AU  - Kaja Kowalska
AU  - Oliver F. Lange
AU  - Roland Wedlich-Söldner
AU  - Don C. Lamb
TI  - Side-binding proteins modulate actin filament dynamics
AID  - 10.1101/008128
DP  - 2014 Jan 01
TA  - bioRxiv
PG  - 008128
4099  - http://biorxiv.org/content/early/2014/08/18/008128.short
4100  - http://biorxiv.org/content/early/2014/08/18/008128.full
AB  - Actin filament dynamics govern many key physiological processes from cell motility to tissue morphogenesis. A central feature of actin dynamics is the capacity of the filament to polymerize and depolymerize at its ends in response to cellular conditions. It is currently thought that filament kinetics can be described by a single rate constant for each end. Here, using direct visualization of single actin filament elongation, we show that actin polymerization kinetics at both filament ends are strongly influenced by proteins that bind to the lateral filament surface. We also show that the less dynamic end, called the pointed-end, has a non-elongating state that dominates the observed filament kinetic asymmetry. Estimates of filament flexibility and Brownian dynamics simulations suggest that the observed kinetic diversity arises from structural alteration. Tuning filament kinetics by exploiting the natural malleability of the actin filament structure may be a ubiquitous mechanism to generate the rich variety of observed cellular actin dynamics.