| Dynamic rearrangements in the actin cytoskeleton underlie a wide range of cell behaviours. |
| Nebulin is a giant protein of skeletal muscle which coextends with actin filaments. |
| The regulation of contractility in striated muscle by calcium is effected via tropomyosin on the actin filament. |
| For example, all three contract when a rise in calcium inside the muscle cell allows interaction between actin and myosin filaments. |
| They use it to convert energy into movement, exerted against polar actin filaments. |
| Briefly, the cardiac myofibrils are composed of the major contractile proteins, actin and myosin. |
