Our lab is captivated by the question of how cells control the rapid assembly and turnover of actin polymer networks to govern cell shape, cell movement, and cell division. The major goal of our research is to understand how cells bring about precise rearrangements of their actin polymer networks, transforming cell shape and function. With hundreds of distinct components and interacting moving parts, actin arrays can be considered self-assembling, work-producing biological machines. Cells deploy a battery of proteins with different, specialized effects to remodel their actin cytoskeletons in response to signals. The goal of our lab is to gain a highly mechanistic and quantitative view of these events. We are focused on two fundamental questions. (1) How is the rapid assembly and disassembly of the actin cytoskeleton governed to produce mechanical forces driving cell motility, endocytosis, polarized growth, and cell division? More specifically, we are defining the in vivo functions and biochemical mechanisms of key, conserved actin-associated proteins (e.g. formins, Arp2/3 complex, cofilin) that bring about dynamic rearrangements in actin networks. This has included the activities of yeast and mammalian formins, a number of formin-binding proteins (e.g. Bud6 and Bud14), Arp2/3 complex-interacting factors (e.g. WASp, Abp1 and coronin), and the actin turnover machinery (e.g. Aip1, twinfilin, and Srv2/CAP). (2) How do other cytoskeletal systems found in eukaryotic cells (microtubules, septins, and intermediate filaments) cooperate with actin polymers to regulate these cellular processes?