Architecture and Dynamics of the Ventral Actin Stress Fiber Network

Abstract

The ventral actin cytoskeleton is a dynamic network of actin stress fibers (VSFs) and focal adhesions that produces contractile forces integral in cell polarization, migration and extracellular matrix remodeling. My research characterizes a novel pathway of VSF remodeling where ventral fibers ‘merge’ at intervening focal adhesions through a process involving contractile bridging through myosin and adhesion disassembly. We examine the mechanosensitive nature of merging by elucidating how the angular orientation of fibers at the adhesion contributes to the efficiency of the process. Merging produces long VSFs that are aligned to the major axis of the cell, functionally determining the mechanobiological signature of the cell. In order to quantitatively analyze stress fibers and associated focal adhesions in datasets, I have created in collaboration, a computational tool FAFCK (Focal Adhesion Filament Cross correlation Kit) which provides a reliable and customizable analysis platform for assessing stress fibers by adhesion association and studying stress fiber subtypes in cells. By creating standalone adhesion and filament analysis modules as well as a correlation function, this software is multifunctional and can be used with several input image types for easy integration into cytoskeletal analysis routines.