Gelsolins (“jell-SOL-ins”) degrade hydrogels containing this protein into sols. Listeria forms “comet tails” of this (20[1])protein to rocket its way through cells. Microscopists image this protein by tagging it with the death cap mushroom’s (20[2])phalloidin (20[2])(“fuh-LOY-din”) toxin. (20[1])At intracellular concentrations that (20[1])can exceed a millimolar, this protein’s globular (20[1])monomer devours (0[1])ATP to rapidly polymerize. (20[1])A cocked head (20[1])forms a cross-bridge (20[1])with this protein and pushes (*) long threads of it backwards during a power (0[1])stroke. (10[1])Assembly of this protein’s fibers at the cell’s leading edge or inside (10[1])pseudo·podia provides flexibility to the cytoskeleton. (10[1]0[2])For 10 points, name this protein which forms thinner filaments than tubulin (0[1])and slides (0[1])past myosin during (10[4])muscle (10[1])contraction. (10[5])■END■ (10[4]0[6])