"How to Build a Cortex: Coordinated Assembly of Cortical Septins and Ac" by Asia Marie Paguntalan

Date of Award

2023

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Microbiology, Molecular Biology and Biochemistry

Abstract

In confined spaces, migrating cells can undergo mesenchymal-to-amoeboid transitions by altering their cortical dynamics and adhesion with the environment. Septins frequently associate with cortical actin and non-muscle myosin (NMII), but the functional nature of these interactions remains unclear. Upon non-adhesive confinement and NMII enrichment, fibroblasts can switch to a fast, leader bleb-based mode of motility, characterized by the absence of adhesions and stress fibers and formation of a single, elongated leader bleb. During this transition, cortical actin remodeling and polarized NMII contractility drive leader bleb stabilization by generating long-range cortical flows, in coordination with changes in septin localization and assembly dynamics. Meanwhile, septin depletion increases global NMII expression, promoting cellular rounding and transient blebbing under non-adhesive confinement. These findings demonstrate the plasticity of fibroblast migration behavior, mediated by cortical septin-actomyosin remodeling and, further, open the door for future studies on the functional relationship between septins and NMII at the cortex.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

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