Scientists always try to design clever experiments, and cross their fingers for clear results. Sometimes a scientist is lucky with both, and results are so intuitive that even a second-grader can see that yes, podosomes are exerting a force able to contribute to cell movement. Check out today’s image, which shows podosomes and their influence on a substrate.
Podosomes are actin-containing structures found where a cell contacts a solid surface. Podosomes can cluster together to form ring structures, and are thought to contribute to the migration of some cell types. Recently, a group of biologists tracked podosome rings and employed some clever tricks to show that podosomes can provide force—specifically for spreading, migration, and retraction of a cell. In one experiment, Hu and colleagues placed osteoclasts (bone cells that remove bone tissue) onto a gel substrate that had beads distributed throughout. By watching how the beads displaced underneath a cell’s podosome rings, it became clear that podosome rings were providing a force that pushed the beads out towards the ring periphery. As seen in the images above, arrows show the direction of the substrate/bead movement while the fluorescent signal shows the actin within the podosome ring.
Hu, S., Planus, E., Georgess, D., Place, C., Wang, X., Albiges-Rizo, C., Jurdic, P., & Geminard, J. (2011). Podosome rings generate forces that drive saltatory osteoclast migration Molecular Biology of the Cell, 22 (17), 3120-3126 DOI: 10.1091/mbc.E11-01-0086