A Caltech Library Service

Membrane shape as a reporter for applied forces

Lee, Heun Jin and Peterson, Eric-L and Phillips, Rob and Klug, William S. and Wiggins, Paul A. (2008) Membrane shape as a reporter for applied forces. Proceedings of the National Academy of Sciences of the United States of America, 105 (49). pp. 19252-19256. ISSN 0027-8424. PMCID PMC2614748. doi:10.1073/pnas.0806814105.

PDF - Published Version
See Usage Policy.

PDF - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


Recent advances have enabled 3-dimensional reconstructions of biological structures in vivo, ranging in size and complexity from single proteins to multicellular structures. In particular, tomography and confocal microscopy have been exploited to capture detailed 3-dimensional conformations of membranes in cellular processes ranging from viral budding and organelle maintenance to phagocytosis. Despite the wealth of membrane structures available, there is as yet no generic, quantitative method for their interpretation. We propose that by modeling these observed biomembrane shapes as fluid lipid bilayers in mechanical equilibrium, the externally applied forces as well as the pressure, tension, and spontaneous curvature can be computed directly from the shape alone. To illustrate the potential power of this technique, we apply an axial force with optical tweezers to vesicles and explicitly demonstrate that the applied force is equal to the force computed from the membrane conformation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Phillips, Rob0000-0003-3082-2809
Additional Information:© 2008 by The National Academy of Sciences of the USA. Edited by L. B. Freund, Brown University, Providence, RI, and approved October 22, 2008 (received for review July 15, 2008). This article is a PNAS Direct Submission. Published online before print December 1, 2008, doi: 10.1073/pnas.0806814105 We thank Robert Bao for the diffusion analysis code; Steve Quake for equipment generously loaned to us; Tristan Ursell, Lin Ma, Feng Feng, Sriram Subramaniam, and Grant Jensen for helpful discussions; and 2 anonymous reviewers for their contributions. Author contributions: H.J.L., E.L.P., R.P., and P.A.W. designed research; H.J.L., E.L.P., and P.A.W. performed research; H.J.L., E.L.P., W.S.K., and P.A.W. analyzed data; and H.J.L., E.L.P., R.P., W.S.K., and P.A.W. wrote the paper. The authors declare no conflict of interest. This article contains supporting information online at We demonstrated the representation independence by making independent tracings of each dataset, which resulted in nearly identical measurements of physically observable quantities. For more information see the SI Appendix.
Subject Keywords:lipid bilayers; membrane mechanics; optical trapping; membrane tethering
Issue or Number:49
PubMed Central ID:PMC2614748
Record Number:CaltechAUTHORS:LEEpnas08
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12512
Deposited By: Archive Administrator
Deposited On:12 Dec 2008 01:05
Last Modified:08 Nov 2021 22:29

Repository Staff Only: item control page