Actin is an essential cytoskeletal protein that plays a critical role in cell mechanics, structure and organization with the help of actin binding proteins (ABPs). Gelsolin is a calcium-dependent ABP that severs actin filaments and caps them at their barbed end, regulating cell motility and signaling through dynamic actin cytoskeleton remodeling. A recent study has indicated that low pH stabilizes the active conformations of gelsolin. Additionally, the binding of gelsolin to the barbed end of an actin filament induces a conformational change that propagates along the actin filament. However, it has not been well understood how the complex intracellular environments involving variations in pH affect gelsolin-mediated actin filament severing and mechanics at the molecular level. In this thesis, we investigate how binding of gelsolin modulates actin filament severing and mechanics with changes in solution pH using total internal reflection fluorescence (TIRF) microscopy imaging. Furthermore, we explore how changes in intra-filament structure and dynamics occur upon gelsolin binding through the use of atomic force microscopy (AFM) imaging. Taken together, this work will elucidate a mechanism to control actin filament severing and mechanics modulated by gelsolin in the pH fluctuating intracellular environment.
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Master of Science (M.S.)
College of Graduate Studies
Nanoscience Technology Center
Length of Campus-only Access
Masters Thesis (Open Access)
Toland, Claire, "Modulation of Actin Filament Severing and Mechanics by Gelsolin in Varying pH Conditions" (2021). Electronic Theses and Dissertations, 2020-. 776.