Myosin light chain kinase becomes in active. A constitutive phosphatase will dephosphorylate myosin 4. Myosin and actin cannot bind. Low rate of ATPase activity makes decreases fatigue. Once the smooth muscle has developed full contraction, the degree of activation can be reduced and the muscle maintain its contraction.
Little energy is consumed.
This protein is caldesmon. Note detachment of actin and myosin by ATP occurs at a slower rate that dephosphorylation of myosin. This may be similar of very different from sk muscle. Action potential is not always required for activation. Input may be excitatory or inhibitory, ie.