Date of Award

12-24-2025

Date Published

January 2026

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics

Advisor(s)

Jennifer Ross

Second Advisor

Jennifer Schwarz

Keywords

Asters;LLPS;Microtubules;Networks;Photoactivation;Tactoids

Subject Categories

Biochemistry, Biophysics, and Structural Biology | Biophysics | Life Sciences

Abstract

Humans have always been trying to unravel principles that guide how things around us function, all the way from galactic ovements to basic building blocks of matter. The physical and chemical properties of ‘biological’ systems govern processes all the way from molecular interactions of proteins to the form and function of individual living organisms. In this work, I focus on the proteins which help give shape and structure to the smallest building block of life, the cell and associated mechanisms of building fundamental cellular architectures, like the mitotic spindle. Mitosis takes place by microtubules aligning themselves in anti-parallel fashion with star-like poles and bringing the chromatin in the center to be pulled apart in equal halves. The formation of mitotic spindle has been an interesting question for a long time. I have attempted to understand this problem with a bottom-up approach by looking at the interaction of microtubules with an antiparallel crosslinking protein which has been known to be present and active during the spindle formation, MAP65/PRC1/ASE1. To that end, I have discussed how the interaction between microtubules and MAP65 can be influenced by varying ionic concentration. I explored in detail using methods like confocal microscopy, gel electrophoresis and single molecule imaging to understand the trends. These nteractions define the microtubule architectures which I have explained using MAP65/PRC1 condensates and their effects on tubulin nucleation and polymerization. This work provides a new mechanism to control in vitro microtubule organization. Biological systems have evolved to work with fantastic efficiencies. Proteins are, after all, molecular machines which do physical work to get these processes done. We have also attempted to harness these properties towards building bio-inspired materials with regulatable properties. Here, I have discussed elastic properties of cytoskeletal networks in presence of opto-genetically engineered crosslinking kinesin motors.

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Open Access

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