ORCID
0000-0002-1013-2619
Keywords
Actin cytoskeleton, Gelsolin, pH, Macromolecular crowding, Molybdenum disulfide, Molybdenum disulfide binding peptide 1
Subject Categories
Cell Biology | Neuroscience and Neurobiology | Other Biomedical Engineering and Bioengineering
Abstract
Actin cytoskeleton dynamics and mechanics are central to many important cellular processes, including cell morphology and motility. Gelsolin is a calcium-regulated actin binding protein involved in filament severing and filament end-capping. Intracellular environmental factors such as pH and macromolecular crowding can regulate actin cytoskeleton remodeling by gelsolin and filament mechanics. However, it is unclear how pH and macromolecular crowding can influence gelsolin-mediated filament severing activities, gelsolin-bound filament bending mechanics and conformations. The first two parts of this dissertation investigate the role of pH and macromolecular crowding on actin dynamics, filament bending stiffness and structures. To determine how intracellular environmental factors modulate gelsolin-mediated actin dynamics, mechanics and conformations, we utilized total internal reflection fluorescence microscopy, pyrene fluorescence assays, and atomic force microscopy. Biophysical analysis demonstrates that acidic pH enhances gelsolin-mediated filament severing and disassembly, and crowding increases filament length reduction by gelsolin. Further, we show that gelsolin binding increases filament flexural rigidity and shortens filament helical half-pitch. The last part of this dissertation investigates the role of molybdenum disulfide (MoS2) nanomaterial and MoS2 binding peptide 1 (MoSBP1) on actin assembly dynamics by fluorescence microscopy imaging and pyrene fluorescence assay. Nanomaterials used in various biomedical applications have been shown to influence cytoskeletal structures and cell morphogenesis. However, it is not known how the individual and combined effects of MoS2 and MoSBP1 influence actin polymerization kinetics and filament mechanics. We show that individual filament elongation and bulk assembly rates are accelerated with MoS2, while MoSBP1 alone inhibits actin assembly. Similarly, MoS2 and MoSBP1 combined reduces actin assembly kinetics. Together, these studies elucidate how gelsolin, intracellular environmental factors, and nanomaterials regulate actin dynamics and mechanics.
Completion Date
2026
Semester
Summer
Committee Chair
Kang, Ellen
Degree
Doctor of Philosophy (Ph.D.)
College
College of Sciences
Department
Physics
Format
Document Type
Dissertation
Language
English
Release Date
8-15-2028
STARS Citation
Douglas, Taylor V., "Actin Cytoskeleton Dynamics, Mechanics and Structures Modulated by Gelsolin, Intracellular Environmental Factors, and Nanomaterials" (2026). Graduate Studies Theses and Dissertations 2026. 260.
https://stars.library.ucf.edu/gradstudies_etd_2026/260
Included in
Cell Biology Commons, Neuroscience and Neurobiology Commons, Other Biomedical Engineering and Bioengineering Commons
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