报告题目：Detailed Physico-Chemical Modeling of Cytoskeletal Dynamics and Motility in Eukaryotic Cells

报 告 人：Garegin A. Papoian，马里兰大学

报告时间：11月2日下午3:00

报告地点：物理系三楼报告厅

报告摘要：Actin polymerization in vivo is regulated spatially and temporally by a web of signaling proteins. We developed a three-dimensional, physico-chemical, stochastic model of sheet-like lamellipodia, which are projected by eukaryotic cells during cell migration, and contain a dynamically remodeling three-dimensional actin mesh. A number of regulatory proteins and subtle mechano-chemical couplings determine the lamellipodial protrusion dynamics. Our work sheds light on how lamellipodial protrusion dynamics is affected by the concentrations of actin and actin-binding proteins. Overall, our work emphasizes that elongation and nucleation processes work highly cooperatively in determining the optimal protrusion speed for the actin mesh in lamellipodia. We also studied molecular mechanisms of growth retraction cycles in filopodia, finger-like protrusions based on bundles of actin filaments. In particular, we found that capping proteins and molecular motors may have a profound effect on filopodial dynamics. We also uncovered the rules of active transport in filopodia, mediated by molecular motors, allowing for highly efficient delivery of cytosolic proteins to the filopodial tip. We studied the concentration profile of motors and actin along the filopodial tube, and the way motor transport couples to filopodial growth dynamics.