Abstract
The assembly of actin filaments into bundles plays an essential role in mechanical strength and dynamic reorganization of cytoskeleton. Divalent counterions at high concentrations promote bundle formation through electrostatic attraction between charged filaments. Although it has been hypothesized that specific cation interactions may contribute to salt-induced bundling, molecular mechanisms of how salt modulates bundle assembly and mechanics are not well established. Here we determine the mechanical and dynamic properties of actin bundles with physiologically relevant cations. Using total internal reflection fluorescence (TIRF) microscopy, we measure the bending stiffness of actin bundles determined by persistence length analysis. We characterize real-time formation of bundles by dynamic light scattering intensity and direct visualization using TIRF microscopy. Our results show that divalent cations modulate bundle stiffness as well as time-dependent average bundle size. Furthermore, molecular dynamic simulations propose specificity for cation binding on actin filaments to form bundles. The work suggests that cation interactions serve a regulatory function in bundle assembly dynamics, mechanics, and structure.
Notes
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Graduation Date
2017
Semester
Spring
Advisor
Kang, Hyeran
Degree
Master of Science (M.S.)
College
College of Graduate Studies
Department
Nanoscience Technology Center
Degree Program
Nanotechnology
Format
application/pdf
Identifier
CFE0006572
URL
http://purl.fcla.edu/fcla/etd/CFE0006572
Language
English
Release Date
May 2018
Length of Campus-only Access
1 year
Access Status
Masters Thesis (Open Access)
STARS Citation
Castaneda, Nicholas, "Mechanism of Actin Bundle Assembly, Mechanics and Structure by Ion Interaction" (2017). Electronic Theses and Dissertations. 5446.
https://stars.library.ucf.edu/etd/5446