 The MYLK2 gene expresses skMLCK more prevalently in fast twitch muscle fibers as compared to slow twitch muscle fibers.Calmodulin is composed of two terminal domains (N,C) each containing two E-F hand motifs that bind to Ca2+.Upon saturation of Ca2+, Calmodulin undergoes a conformation change allowing it to bind with a target protein such as skMLCK.