This lecture covers the biochemical basis of actin-based motility (focusing on the pathogen Listeria as a model system for this process), the biophysical mechanism of polymerization-based force generation, and an evolutionary perspective of cell shape in prokaryotes and eukaryotes. The first part covers our understanding of how cells use the actin cytoskeleton to crawl. The pathogenic bacteria Listeria (which causes food poisoning) uses the actin cytoskeleton to propel itself in the cytoplasm and also invade other cells. This system has been an important model for understanding the actin cytoskeleton at the leading edge of a motile cell and for understanding host-pathogen interactions.
In her seminar, Dr. Theriot describes a thermodynamic model that proposes a mechanism by which the energy associated with a polymerizing cytoskeletal filament can be converted to force for cell movements. What predictions of the model would you measure in order to test the idea that the proposed mechanism is used to propel a Listeria bacterium through cytoplasm in infected cells and how might this illuminate the mechanism of neutrophil motility in the blood?