<prompt> Smooth muscle contraction due to release of calcium, occurs because of ?Increased cAMPCalcium combining with troponin CIncreased cGMPCalmodulin-dependant myosin light chain kinase  <response>: In Smooth muscles, rise in intracellular leads to binding of 4 Ca ions with calmodulin. Calcium-calmodulin complex then activates myosin light chain kinase MLCK. MLCK phosphorylates the regulatory light chain of myosin; this phosphorylation then leads to interaction of myosin with actin. Calmodulin is structurally and functionally related to troponin. Troponin is present in skeletal muscles and initiates contraction by causing a conformational change in the tropomyosin molecule which then uncovers the active sites on the actin filament. 