Force generation in lamellipodia is a probabilistic process with fast growth and retraction events

Shahapure, Rajesh, Difato, Francesco, Laio, Alessandro , Bisson, Giacomo, Ercolini, Erika, Amin, Ladan, Ferrari, Enrico and Torre, Vincent (2010) Force generation in lamellipodia is a probabilistic process with fast growth and retraction events. Biophysical Journal, 98 (6). pp. 979-988. ISSN 0006-3495

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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 μm 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.

Keywords:optical tweezers, lamellipodia, actin
Subjects:C Biological Sciences > C770 Biophysical Science
B Subjects allied to Medicine > B140 Neuroscience
Divisions:College of Science > School of Life Sciences
ID Code:6585
Deposited On:15 Oct 2012 20:47

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