Dr. Elena Koslover

"Emergent Physical Phenomena: from Biomolecules to Living Cells"

About the Seminar

The internal microenvironment of a cell comprises an intricate choreography of molecules that must be transported from one location to another, elastic forces that must be overcome or harnessed into useful work, and interdependent chemical reactions whose rates must be carefully controlled. Using multi-scale models grounded in statistical physics and continuum mechanics, we study physical chemistry inside the cell. This talk will focus on how collective physical phenomena arise from biomolecular constituents and how they impact biological function.

The mechanical properties of DNA as a semiflexible "worm-like" chain play a critical role in the packaging and accessibility of the genome. The elasticity of this chain contributes to interactions between DNA-binding proteins and impacts the formation of chromatin fibers that serve as the lowest level of genome organization. On a whole-genome scale, DNA provides a complicated landscape for the dynamics of target site search by regulatory proteins. The wide range of length scales relevant to the behavior of biopolymers such as DNA necessitate the development of efficient and accurate coarse-graining methods. A novel technique for systematically mapping polymer models to effective semielastic chains that are both analytically tractable and suitable for large-scale simulation will be discussed.

At the cellular level, the complex mechanics of the cytoplasm emerges from a combination of active forces and heterogeneous material conditions. The cytoplasm of motile cells provides a uniquely dynamic intracellular environment for studying the interplay of these effects. Using newly developed techniques for analyzing microrheological data in moving systems, we demonstrate that the cytoplasm of neutrophils behaves as a viscous fluid whose flows dominate intracellular particle motion. The dynamics of these cells further motivates the study of mixing and reactions inside fluctuating confined fluid domains.

From individual DNA-protein interactions to dynamic whole-cell deformations, this talk will highlight the importance of large-scale physical phenomena in the structure and function of living cells. 

About the Speaker

Elena Koslover received her BS degrees in mathematics and biology from Caltech in 2006. The following year, she went on to receive an MPhil in Chemistry from the University of Cambridge as a Churchill Scholar working with Prof. David Wales on algorithm development for transition state search problems. Funded by the NSF Graduate Research Fellowship and a fellowship from the Fannie and John Hertz Foundation, she completed her PhD in Biophysics at Stanford University in 2013. Her thesis work with Prof. Andrew Spakowitz focused on theoretical and computational modeling of DNA mechanics as it impacts the packaging and accessibility of the genome. A recipient of the James S. McDonnell Foundation Postdoctoral Fellowship in Studying Complex Systems, she is currently a postdoctoral scholar with Prof. Julie Theriot in the Biochemistry Department at Stanford. Her work centers on understanding collective physical phenomena in the intracellular environment.