All of the following are true statements about electromechanical coupling, EXCEPT:
In smooth muscle, Ca2+ ions bind to calmodulin Smooth muscle contraction is initiated by myosin light chain phosphorylation In cardiac muscle, Ca2+ ions bind to troponin The major source of Ca2+ ions for contraction of skeletal muscle is influx of Ca2+ ions from the extracellular space following voltage-dependent opening of L-type Ca2+ channels.