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Article Dans Une Revue Molecular Biology of the Cell Année : 2011

Turnover of branched actin filament networks by stochastic fragmentation with ADF/cofilin.

Résumé

Cell motility depends on the rapid assembly, aging, severing, and disassembly of actin filaments in spatially distinct zones. How a set of actin regulatory proteins that sustains actin-based force generation during motility work together in space and time remains poorly understood. We present our study of the distribution and dynamics of Arp2/3 complex, capping protein (CP), and actin-depolymerizing factor (ADF)/cofilin in actin "comet tails," using a minimal reconstituted system with nucleation-promoting factor (NPF)-coated beads. The Arp2/3 complex concentrates at nucleation sites near the beads as well as in the first actin shell. CP colocalizes with actin and is homogeneously distributed throughout the comet tail; it serves to constrain the spatial distribution of ATP/ADP-P(i) filament zones to areas near the bead. The association of ADF/cofilin with the actin network is therefore governed by kinetics of actin assembly, actin nucleotide state, and CP binding. A kinetic simulation accurately validates these observations. Following its binding to the actin networks, ADF/cofilin is able to break up the dense actin filament array of a comet tail. Stochastic severing by ADF/cofilin loosens the tight entanglement of actin filaments inside the comet tail and facilitates turnover through the macroscopic release of large portions of the aged actin network.

Dates et versions

hal-00607272 , version 1 (08-07-2011)

Identifiants

Citer

Anne-Cécile Reymann, Cristian Suarez, Christophe Guérin, Jean-Louis Martiel, Christopher J Staiger, et al.. Turnover of branched actin filament networks by stochastic fragmentation with ADF/cofilin.. Molecular Biology of the Cell, 2011, 22 (14), pp.2541-50. ⟨10.1091/mbc.E11-01-0052⟩. ⟨hal-00607272⟩
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