Direct measurement of the lamellipodial protrusive force in a migrating cell

Citations Over TimeTop 10% of 2006 papers

Abstract

There has been a great deal of interest in the mechanism of lamellipodial protrusion (Pollard, T., and G. Borisy. 2003. Cell. 112:453-465). However, one of this mechanism's endpoints, the force of protrusion, has never been directly measured. We place an atomic force microscopy cantilever in the path of a migrating keratocyte. The deflection of the cantilever, which occurs over a period of approximately 10 s, provides a direct measure of the force exerted by the lamellipodial leading edge. Stall forces are consistent with approximately 100 polymerizing actin filaments per micrometer of the leading edge, each working as an elastic Brownian ratchet and generating a force of several piconewtons. However, the force-velocity curves obtained from this measurement, in which velocity drops sharply under very small loads, is not sensitive to low loading forces, and finally stalls rapidly at large loads, are not consistent with current theoretical models for the actin polymerization force. Rather, the curves indicate that the protrusive force generation is a complex multiphase process involving actin and adhesion dynamics.

Related Papers

• → The Ordered Extension of Pseudopodia by Amoeboid Cells in the Absence of External Cues(2009)170 cited
• → Unified control of amoeboid pseudopod extension in multiple organisms by branched F-actin in the front and parallel F-actin/myosin in the cortex(2020)13 cited
• → ADictyostelium myosin I plays a crucial role in regulating the frequency of pseudopods formed on the substratum(1996)77 cited
• → Microtubules are required in amoeba chemotaxis for preferential stabilization of appropriate pseudopods(1994)30 cited
• → Experimental study of the effect of hydrodynamic coupling of micro-cantilever array on the dynamic response of micro-cantilever(2010)1 cited