Elastic Brownian Ratchets and Tethered filaments Images removed due to copyright considerations See Mogilner, A and G. Oster Force generation by actin polymerization lI: the elastic ratchet and tethered filaments Biophys J.2003Mar;84(3):1591605 Brownian Actin filament tips fluctuate Some filaments are tethered
Elastic Brownian Ratchets and Tethered Filaments Images removed due to copyright considerations. See Mogilner, A. and G. Oster. "Force generation by actin polymerization II: the elastic ratchet and tethered filaments��." Biophys J. 2003 Mar;84(3):1591-605. Brownian: Actin filament tips fluctuate Some filaments are tethered 6
Actin Ruffles in Motile Cells
Actin Ruffles in Motile Cells 7
Supramolecular Springs Energy stored in chemical bonds which act as "latches Regulated by spasmin Calcium binding protein Images removed due to copyright considerations See Mahadevan L. and P. matsudaira Motility powered by supramolecular springs and ratchets. Science.2000Apr7;288(5463):95-100
Supramolecular Springs Energy stored in chemical bonds which act as “latches’ Regulated by Spasmin: Calcium binding protein Images removed due to copyright considerations. See Mahadevan, L. and P. Matsudaira. "Motility powered by supramolecular springs and ratchets." Science. 2000 Apr 7;288(5463):95-100. 8
Horseshoe Crab Sperm Uncoiling of an actin spring (unlike the echinoderm sperm-no polymerization!) Images removed due to copyright considerations See mahadevan L. and P. matsudaira Motility powered by supramolecular springs and ratchets Science.2000Apr7;288(5463)95-100
Horseshoe Crab Sperm Uncoiling of an actin spring (unlike the echinoderm sperm - no polymerization!) Images removed due to copyright considerations. See Mahadevan, L. and P. Matsudaira. "Motility powered by supramolecular springs and ratchets." Science. 2000 Apr 7;288(5463):95-100. 9
Molecular Motors Molecules that convert chemical energy into mechanical force Motors are specialized for specific tasks cell division cell movement organelle transport synthesis of ATP Most move unidirectionally along polymer filaments Coupled mechanical and chemical cycles(fuel)
Molecular Motors • Molecules that convert chemical energy into mechanical force • Motors are specialized for specific tasks: cell division cell movement organelle transport synthesis of ATP • Most move unidirectionally along polymer filaments • Coupled mechanical and chemical cycles (fuel) 10