Abstract

Actin is a highly abundant protein in most eukaryotic cells. The assembly of actin monomers to double helical filaments is crucial for many cellular functions, including cell movement and cell division. Actin filament assembly in cells occurs in a crowded intracellular environment consisting of various molecules, including cations and organic osmolytes. Recent studies show that cation binding stiffens actin filaments, and a small organic osmolyte trimethylamine-N-oxide (TMAO) modulates filament assembly. However, how cations and TMAO combined affect actin filament mechanics is not understood. We hypothesize that depending on the concentrations of cations and osmolytes, there will be different effects on the stiffness and assembly of actin filaments. In this study, using TIRF we evaluate actin filament mechanics and assembly. Our findings indicate that when TMAO is present alone, it can increase the elongation rate and stiffness of actin filaments, however the inclusion of potassium levels alongside TMAO reduces the persistence length of actin filaments, suggesting a decrease in filament stiffness compared to the influence of TMAO alone. Furthermore, the elongation rate of actin filaments decreases when both TMAO and potassium ions are present. This study will help us better understand how cations and osmolytes together can affect actin filament mechanics in the living cells.

Thesis Completion

2023

Semester

Fall

Thesis Chair/Advisor

Kang, Ellen

Degree

Bachelor of Science (B.S.)

College

College of Sciences

Department

Physics

Language

English

Access Status

Campus Access

Length of Campus-only Access

1 year

Release Date

12-15-2024

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