Elementary contractile unit and collective motor behavior

After introducing the main features characterizing an elementary contractile unit in cells as studied in M Sheetz lab in Singapore and Columbia New-York, I will recall theoretical results concerning motor collections obtained over the years. In particular I will show how a symmetry breaking transition, emergent feature of a large number of molecular motor collection, underpins a number of biological functions such as muscle oscillations. I will then show how a simple modification of the theoretical framework allows to understand all experimental observations including force build-up followed by a relaxation and the existence of half integer steps in the contraction/relaxation curve, which is a resurgence of a nanoscopic scale in a mesoscopic system.

Myosin filaments reversibly generate large forces in cells
J Lohner, JF Rupprecht, et al Nature Physics 2019