Migration fingers are the spirit fingers of a migrating epithelial sheet of cells. Woowoo!! Today’s image is from a cool paper on the forces exerted by a migration finger, so naturally I’m showing my enthusiasm with my own spirit fingers.
Cells can migrate on their own or as part of an epithelial sheet of many cells. Collective migration features the forward movement of multicellular migration fingers, and can be seen throughout development, in spreading tumors and in healing wounds. The formation of each migration finger begins with the transformation of a single cell into a leader cell. A recent paper looks at leader cells and migration fingers, specifically the biochemical mechanisms involved and the generation of forces exerted by migration fingers. Reffay and colleagues monitored the traction forces exerted by a migration finger, and found that the leader cell exerts a large mechanical force that drags its followers with the help of the small GTPase RhoA. In the images above, the contractile acto-myosin cable that runs the length of the migration finger is cut by laser photoablation (arrow, middle). A new leader cell is formed at the site of the cut (asterisk, right), suggestion that the cable serves to prevent the formation of new leader cells, which in turn allows the formation of long migration fingers.
Reffay, M., Parrini, M., Cochet-Escartin, O., Ladoux, B., Buguin, A., Coscoy, S., Amblard, F., Camonis, J., & Silberzan, P. (2014). Interplay of RhoA and mechanical forces in collective cell migration driven by leader cells Nature Cell Biology, 16 (3), 217-223 DOI: 10.1038/ncb2917
Adapted by permission from Macmillan Publishers Ltd, copyright ©2014