Discussion of “Cytoskeletal Mechanics Regulating Amoeboid Cell Locomotion” (Álvarez-González, B., Bastounis, E., Meili, R., del Alamo, J. C., Firtel, R. A., and Lasheras, J. C., 2014, ASME Appl. Mech. Rev., 66(5), p. 050804)

Xavier Trepat

doi:10.1115/1.4027258

Abstract

A virtually universal feature of adherent cells is their ability to exert traction forces. To measure these forces, several methods have been developed over the past 15 years. In this issue of Applied Mechanics Reviews, Álvarez-González and co-workers review their own traction force microscopy approach and its application to the study of amoeboid cell locomotion. They show that the cycle of cell motility is exquisitely synchronized by a cycle of traction forces. In addition, they show how traction forces and cell cycle synchronization are affected by myosin and SCAR/WAVE mutants. Here, I discuss some open questions that derive from the work of the authors and other laboratories as regards the relationship between cell motility and traction forces.

Highlights

For more than 250 years, physicists have known that motion of any object, living or inert, cannot be fully understood except in the context of physical forces
The earliest versions of traction microscopy assumed that forces applied by cells on their underlying flat substrates were essentially two‐dimensional [6, 7]; forces in the the dimension normal to the plane of cell adhesion, were thought to be either negligible or biologically irrelevant
While the cyclic nature of amoeboid migration has been known for a long time [13], the authors performed a systematic analysis of the traction forces generated during each step of the cycle

Summary

Introduction

For more than 250 years, physicists have known that motion of any object, living or inert, cannot be fully understood except in the context of physical forces. The earliest versions of traction microscopy assumed that forces applied by cells on their underlying flat substrates were essentially two‐dimensional [6, 7]; forces in the the dimension normal to the plane of cell adhesion, were thought to be either negligible or biologically irrelevant. This notion was somehow supported by the observation that contractile stress fibers in adherent cells were essentially basal and parallel to the substrate.

Results

Conclusion