London – The contraction of striated, skeletal and heart muscle stems from sliding of two types of superimposed protein filaments: the myosin filament that carries molecular motors and that of actin which works as a binary for the motors. The presence of a dual regulation system for muscle contraction has been demonstrated by a group of scientists from the University of Florence and King’s College London, in collaboration with the ESRF synchrotron in Grenoble (European Synchrotron Radiation Facility), in a research published in Nature (DOI 10.1038 / nature15727). According to the classical view, muscle contraction is controlled by a structural change in actin filaments induced by ionized calcium. This allows the attachment of myosin molecular motors that extend from surrounding myosin filaments and induce the relative sliding of the two strands. “The results of our study – explains Vincenzo Lombardi, professor of Physiology at the University and coordinator of the international research group – show that muscle contraction is controlled by two switches: the actin filament which transmits the signal to the nervous system central, and the myosin filament which adapts the response of the muscle to the external load, ensuring maximum efficiency”. (9Colonne)
