P PANGAMANI (UCSD)

"Membrane Tension & Actin Organization in Clathrin-Mediated Endocytosis" Cells use the polymerization of actin filaments to convert polymerization energy into mechanical work. In the case of endocytosis, actin polymerization generates force to bend and pull a small region of the plasma membrane into a round vesicle for internalizing transmembrane and extracellular cargo. Despite detailed knowledge of the biochemical function of individual actin cytoskeletal proteins, the mechanism by which they work collectively to bend and pull the plasma membrane in cells is not understood, particularly in metazoan cells. Here, we use a combination of membrane mechanics and actin filament dynamics to explore how actin is organized around endocytic sites. Three-dimensional, stochastic simulations of the model revealed that Arp2/3-nucleated actin networks self-organize into a dendritic cone focused against the attachment site at the base of the endocytic vesicle. This work is part of a larger effort in my group to explore how geometry, mechanics, and chemical interactions come together to dictate structure-function relationships in cells.