Happy New Year! To kick off 2013 properly, today I’m featuring an image from a lab whose leader is one of the coolest cats in cell biology (click here for proof). The image is from a paper describing the nanoscale forces within individual focal adhesions, and how these forces guide cell migration.
“Durotaxis” is the directed cell migration along a rigidity gradient—meaning the migration toward a more mechanically stiff extracellular matrix (ECM). Durotaxis occurs throughout development and cancer metastasis, two situations during which the stiffness of a tissue can vary locally or over time. A recent paper describes how cells sample the environment to sense ECM stiffness, and how this sampling guides migration of a cell toward stiff ECM. Using high-resolution time-lapse traction force microscopy, Plotnikov and colleagues documented the forces within individual focal adhesions (FAs) in migrating cells. These individual FAs tug on the ECM to function as local sensors of ECM rigidity. This tugging traction is necessary for durotaxis, but not chemotaxis, another type of cell migration. In the images above, paxillin is fluorescently labeled to show FAs (top, left and zoomed image on right). The corresponding heatmaps (bottom, left and right) show the magnitudes of tugging forces on the ECM (FAs outlined in black), while the stress vector field image (middle right) shows the direction of the forces within the FAs.
Plotnikov, S., Pasapera, A., Sabass, B., & Waterman, C. (2012). Force Fluctuations within Focal Adhesions Mediate ECM-Rigidity Sensing to Guide Directed Cell Migration Cell, 151 (7), 1513-1527 DOI: 10.1016/j.cell.2012.11.034
Copyright ©2013 Elsevier Ltd. All rights reserved.