JCB logo
AbD Serotec
  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents
Published 11 September 2006. doi:10.1083/jcb.200601159
The Rockefeller University Press, 0021-9525 $8.00
JCB, Volume 174, Number 6, 767-772
This Article
Right arrow Full Text
Right arrow Full Text (PDF, 899K)
Right arrow PPT slides of all figures
Right arrow Supplemental Material Index
Right arrow Alert me when this article is cited
Right arrow Citation Map
Services
Right arrow Email this article
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new content in the JCB
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Prass, M.
Right arrow Articles by Radmacher, M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Prass, M.
Right arrow Articles by Radmacher, M.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Facebook   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Report

Direct measurement of the lamellipodial protrusive force in a migrating cell



Marcus Prass1, Ken Jacobson2,3, Alex Mogilner4,5, and Manfred Radmacher1

1 Institute of Biophysics, University of Bremen, D-28359 Bremen, Germany
2 Department of Cell and Developmental Biology and 3 Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
4 Department of Mathematics and 5 Center for Genetics and Development, University of California, Davis, Davis, CA 95616

Correspondence to Manfred Radmacher: mr{at}biophysik.uni-bremen.de

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 ~10 s, provides a direct measure of the force exerted by the lamellipodial leading edge. Stall forces are consistent with ~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.

Abbreviations used in this paper: AFM, atomic force microscopy; RICM, reflection interference contrast microscopy.


Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Facebook Facebook   Add to Reddit Reddit   Add to Technorati Technorati   Add to Twitter Twitter    What's this?


This article has been cited by other articles:



  Home | Help | Feedback | Subscriptions | Archive | Search | Table of Contents