[Are the reciprocal sliding of protofibrils and the shortening of thick filaments during muscle contraction based on a common molecular mechanism?].

It is assumed that the back stroke of myosin bridges in a contracting fibre is determined by nucleotide binding. Then an inhibition of actomyosin dissociation can lead to the shortening of the thick filaments. Possible existence of a protein control system, suppressing this dissociation is discussed.