‘Active Matter’ Research Explores How Biological Systems Put Themselves Together

How do spindles form and chromosomes move? The Biophysical Modeling group of the Center for Computational Biology seeks to understand the inner dynamics of the cell.

The centrosomal arrays of nuclear complexes are involved in the complex’s positioning prior to cell division, but exactly how this happens is unclear. This simulation investigates one model of the process, wherein microtubules in the array grow and push against the cell wall before depolymerizing, and in this way slowly center and rotate the complex into its proper place and orientation. The shapes of the dynamical microtubules and the flows of cytoplasm within the cell are signatures of particular positioning models. These shapes can be compared with the results of an experiment to help identify how forces are transduced within the cell to accomplish this crucial function. Work by Ehssan Nazockdast and Michael Shelley of CCB

The DNA inside a cell’s chromosomes contains a blueprint for assembling and regulating all the cell’s proteins, but that blueprint is not simply lying open, waiting to be read. Instead, tiny ‘machines’ within the cell are constantly thumbing through the pages, moving the fibers of DNA to bring certain regions together into useful combinations. And when a cell divides, the chromosomes get moved about even more: A spindle structure pushes and pulls them into formation and escorts them into the newly born cells.

“All of this movement factors into how cells work and how they divide,” says Michael Shelley, leader of the biophysical modeling group at the Center for Computational Biology in the Flatiron Institute, a division of the Simons Foundation. “It’s not just a matter of molecules and chemical reactions — there’s physics in there, and fluid dynamics too.”