Cell motility and cell migration
Tuesday, April 24, 2012 – 3:30pm – 4:30pm
Department of Physics and Astronomy, University of Pennsylvania
T cells are among the cells in our immune system that hunt down and kill pathogens. I will first discuss the physical mechanisms underlying how cells such as T cells move. When a cell crawls, its shape must change, and it must reorganize the network of filaments that controls its shape. During cell crawling, various processes drive the self-assembly of the protein actin into a branched network of filaments. I will present a new picture of the mechanism by which this far-from-equilibrium self-assembly process gives rise to motility. I will then turn to the nature of the migration tracks of T cells. We have found that migration statistics of T cells in brains infected with the parasite Toxoplasma gondii are similar those of predators such as sharks as they hunt their prey. Instead of performing a Brownian random walk, as had been assumed in previous studies, T cells perform generalized Lévy walks, consisting of Lévy-distributed runs alternating with pauses of Lévy-distributed durations. According to our model, this strategy enables T cells to find rare targets more than an order of magnitude more efficiently than Brownian random walkers.
Host: Paola Barbara