Polymerization of actin filaments is the primary source of motility in lamellipodia and it is controlled by a variety of regulatory proteins. The underlying molecular mechanisms are only partially understood and a precise determination of dynamical properties of force generation is necessary. Using optical tweezers, we have measured with millisecond (ms) temporal resolution and picoNewton (pN) sensitivity the force-velocity (Fv) relationship and the power dissipated by lamellipodia of dorsal root ganglia neurons. When force and velocity are averaged over 3-5 s, the Fv relationships can be flat. On a finer timescale, random occurrence of fast growth and subsecond retractions become predominant. The maximal power dissipated by lamellipodia over a silica bead with a diameter of 1 mu m is 10(-16) W. Our results clarify the dynamical properties of force generation: i), force generation is a probabilistic process; ii), underlying biological events have a bandwidth up to at least 10 Hz; and iii), fast growth of lamellipodia leading edge alternates with local retractions.
|Titolo:||Force generation in lamellipodia is a probabilistic process with fast growth and retraction events|
|Autori:||Shahapure, R; Difato, F; Laio, A; Bisson, G; Ercolini, E; Amin, L; Ferrari, E; Torre, V.|
|Data di pubblicazione:||2010|
|Digital Object Identifier (DOI):||10.1016/j.bpj.2009.11.041|
|Fulltext via DOI:||10.1016/j.bpj.2009.11.041|
|Appare nelle tipologie:||1.1 Journal article|