APS March Meeting 2024
Monday–Friday, March 4–8, 2024;
Minneapolis & Virtual
Session S27: Biological Active Matter III
8:00 AM–11:00 AM,
Thursday, March 7, 2024
Room: 101H
Sponsoring
Units:
DBIO DSOFT GSNP
Chair: Leila Abbaspour, Max Planck Institute for Dynamics and Self-Organization
Abstract: S27.00015 : Principles of cellular behavior: integrating cellular structure, dynamics, and decision making
10:48 AM–11:00 AM
Abstract
Presenter:
Ben T Larson
(University of California, San Francisco)
Author:
Ben T Larson
(University of California, San Francisco)
Although it may be easy to think of cells as the simple building blocks of more complex organisms such as animals, single cells are capable of remarkably sophisticated behaviors such as navigating dynamic environments, hunting prey, and evading predation. These behaviors emerge from the interactions among myriad molecular components in conjunction with physical constraints and mechanisms that dictate interactions between the cell and its environment. The ciliate Euplotes, a cell that walks across surfaces using motile appendages (cirri) composed of bundles of cilia, is an ideal system for navigating this mechanistic complexity due to its extensive behavioral repertoire that is amenable to rigorous analysis. Analyses drawing on ideas from non-equilibrium physics and computer science revealed finite state machine-like processing embodied in walking Euplotes eurystomus cells. Cellular walking entails regulated transitions between a discrete set of gait states with stereotypy in sequential patterns of state transitions. Simulations and experiments suggest that the sequential logic of the gait is functionally important. Taken together, these findings implicate a finite-state machine-like process. Cirri are connected by microtubule bundles (fibers), and the dynamics of cirri involved in different state transitions are associated with the structure of the fiber system. Perturbative experiments revealed that the fibers mediate gait coordination at fast timescales, suggesting a mechanical basis of gait control, and implicate intracellular signaling involving Ca2+ and cGMP in dictating overall cirral activity levels. Comparisons among Euplotes species show a complex scaling relationship between cell structure and movement patterns. Cell movement patterns are stereotyped, species specific, and dictated by environmental conditions as well as cell state over multiple timescales. These results highlight the role of physical and developmental constraints in the evolution of cellular behavior. Ultimately, we aim to elucidate general principles of the regulation and evolution of cellular behavior by integrating understanding across scales of biological organization, linking cellular structure and physiology to patterns of behavior to environmental contexts.