Locating muscle proteins: Scientists bring the basis of muscle movement into sharper focus
Muscle contraction and many other movement processes are controlled by the interplay between myosin and actin filaments. Two further proteins, tropomyosin and troponin, regulate how myosin binds to actin. While theoretical models have in fact described exactly how these muscle proteins interact, this interaction has never previously been observed in detail. Stefan Raunser and Elmar Behrmann from the Max Planck Institute of Molecular Physiology in Dortmund have now managed to image the actin-myosin-tropomyosin complex with an unprecedented accuracy of 0.8 nanometres, which amounts to a resolution of less than one-millionth of a millimetre. This has, for the first time, made it possible to correctly identify the location of proteins within the complex and to analyse the processes involved in muscle contraction. These findings could help determine the impact of genetically determined modifications to the actin-myosin-tropomyosin complex in certain types of hereditary heart disease.
