Speaker: Sonya Hanson, Ph.D.
Title: Two approaches to understanding the effect of temperature on biological systems
Abstract: In this talk, I will discuss two recent projects that improve our understanding of how temperature affects biological systems, though in different contexts. I will first introduce some concepts around biological temperature sensors and then describe the first of these projects, which is a double-well toy model of a simple temperature sensor. I will discuss how this project has implications for our existing understanding of the temperature sensitive TRP family of ion channels, which as the most well-studied biological temperature sensors has broad implications for our understanding of other temperature sensors. The study of TRP channels by cryo-EM is also a key aspect of how we understand their function, and the second part of the talk will focus on a recent preprint we have studying, via MD simulations, how the process of vitrification in cryo-EM effects the conformational distribution we observe in cryo-EM data. This project concludes with a method for recovering the pre-vitrified ensemble populations from the populations of states observed in cryo-EM. Together, these two projects highlight how computational approaches can sharpen our interpretation of experimental data and deepen our mechanistic understanding of temperature sensation.
Speaker: David Stein, Ph.D.
Title: A flexible simulation tool for flexible cytoskeletal elements
Abstract: The turbulence of active nematic fluids, exemplified by microtubule–kinesin suspensions, has been widely studied in regimes populated by half-integer topological disclinations. Here, we instead investigate defect-free regimes, revealing the dramatic impact of two overlooked control parameters. First, the flow-alignment coupling is shown to enhance chaotic flows in contractile nematics while promoting a striking arrested state in extensile ones, where coherent streams are channeled through a tree-like network of nematic domain walls. Second, the ratio of the nematic healing length to the active length scale is shown to determine whether domain walls persist or instead give way to defects that dissolve them. These findings provide mechanistic insight into active nematic organization and suggest strategies for future experimental control and analysis.